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The analysis of perinatal studies is complicated by twins and other multiple births even when multiples are not the exposure, outcome, or a confounder of interest. In analyses of infant outcomes restricted to live births, common approaches to handling multiples include restriction to singletons, counting outcomes at the pregnancy level (i.e., by counting if at least one twin experienced a binary outcome), or infant-level analysis including all infants and accounting for clustering of outcomes, such as by using generalized estimating equations or mixed effects models. Several healthcare administration databases only support restriction to singletons or pregnancy-level approaches. For example, in MarketScan insurance claims data, diagnoses in twins are often assigned to a single infant identifier, thereby preventing ascertainment of infant-level outcomes among multiples. Different approaches correspond to different questions, produce different estimands, and often rely on different assumptions. We demonstrate the differences that can arise from these different approaches using Monte Carlo simulations, algebraic formulas, and an applied example., Competing Interests: Disclosure: K.F.H. is an investigator on grants to her institution from UCB and Takeda, unrelated to this work. S.H.-D. reports being an investigator on research grants to her institution from Takeda and consulting for Moderna, UCB, and Jansen; all unrelated to the present study. All other authors report no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

In recent decades, the use of assisted reproductive technology (ART) has increased rapidly. To assess the relationship between ART and autism diagnosis, we linked California birth records from 2000 through 2016 with contemporaneous records from the National ART Surveillance System (NASS) and autism caseload records from California's Department of Developmental Services from 2000 through November 2019. All 95 149 birth records that were successfully linked to a NASS record, indicating an ART birth, were matched 1:1 using propensity scores to non-ART births. We calculated the hazard risk ratio for autism diagnosis and the proportions of the relationship between ART conception and autism diagnosis mediated by multiple birth pregnancy and related birth complications. The hazard risk ratio for autism diagnosis following ART compared with non-ART conception is 1.26 (95% CI, 1.17-1.35). Multiple birth, preterm birth, and cesarean delivery jointly mediate 77.9% of the relationship between ART conception and autism diagnosis. Thus, increased use of single embryo transfer in the United States to reduce multiple births and related birth complications may be a strategy to address the risk of autism diagnosis among ART-conceived children., (Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health 2024.)

Objective: To investigate the effect of the Assisted Reproduction Act, implemented in 2007 in Taiwan to reduce the number of embryos to transfer, on the trends over time regarding the rate of multiple births, preterm delivery, low birth weight (LBW), and small for gestational age (SGA) among deliveries using assisted reproductive technology (ART)., Study Design: From the Birth Reporting Registry and the Assisted Reproduction Registry, we retrieved data of 4 016 530 live birth deliveries between 2001 and 2020; among them 71 000 (1.77%) were after ART. We calculated the rate of multiples and perinatal outcomes per 1000 deliveries annually from 2001 to 2020 for deliveries using and not using ART and computed the population attributable risk. We performed interrupted time series to assess the effect of the intervention, ie, the Assisted Reproduction Act., Results: The proportion of deliveries following ART was 0.57% in 2001 and increased to 4.03% in 2020. After the intervention, there were decreasing trends over time for rates of multiples (-10.63 per year, P < .001), preterm delivery (-6.74, P = .003), LBW (-9.38, P < .001), and SGA (-4.48, P = .001) among ART deliveries. There was also an immediate decrease right after intervention (-53.45, P = .005) for SGA after ART. The population attributable risk trends before and after intervention were both increasing for all outcomes., Conclusions: The Assisted Reproduction Act in Taiwan was associated with a decreasing trend of multiples, preterm delivery, LBW, and SGA over time since 2008 among ART deliveries. In particular, there was an immediate decrease of SGA right after the intervention., Competing Interests: Declaration of Competing Interest The authors declare no conflicts of interest., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Multiple births strain mothers' and families' resources in ways that should highlight preferences for family size, birth spacing, and parity-dependent stopping behavior. Couples with surviving twins reach their target family size sooner than other couples and should be more likely to practice family limitation. Twins are also a greater burden on the mother's time and health, which could lead to postponing the next birth, even among couples who want additional children. We examine these hypotheses by analyzing families with twins in the 1900 and 1910 U.S. Censuses. Using reconstructed birth histories for more than 7 million women in the IPUMS full-count 1900 and 1910 datasets and event-history methods (Kaplan-Meier curves, cure models), we find clear evidence of family limitation following a multiple birth. Couples who had twins or triplets were more likely to stop childbearing, and those who continued having children delayed their next birth. Responses to multiple births were larger in groups previously identified as leaders in the transition to smaller families, and roughly one third of couples stopped after one or two children. We find no evidence that some groups relied primarily on birth spacing to reduce family size while others relied primarily on stopping., (Copyright © 2024 The Authors.)

Objectives: This report explores changes in the overall rate of triplet and higher-order births from 1998 to 2023 by detailed plurality, maternal race and Hispanic origin, and age., Methods: Data are from the National Vital Statistics System birth files. Triplet and higher-order birth rates (number of triplet and higher-order births per 100,000 births) from 1998 to 2023 are presented. Also presented are the number of triplet, triplet and higher-order, and quadruplet and higher-order births, and triplet and higher-order multiple birth rates by maternal race and Hispanic origin and maternal age for 1998, 2009, and 2023., Results: From 1998 to 2023, the triplet and higher-order multiple birth rate declined 62%, from 193.5 per 100,000 total births to 73.8; the largest declines were from 2009 to 2023. The number of triplet and higher-order births declined from 7,625 to 2,653. Declines in triplet and higher-order birth rates were observed for White non-Hispanic (71%) and Hispanic (25%) mothers, while the rate for Black non-Hispanic mothers increased (25%). Triplet and higher-order birth rates declined for all age groups 20 and older from 1998 to 2023, and the largest declines were for mothers age 30 and older.

Objective: To evaluate the relative impact of different strategies of medically assisted reproduction (MAR), i.e. first line treatment (ovarian stimulation with or without intrauterine insemination) and in vitro fertilization (IVF) procedures (conventional IVF or intracytoplasmic sperm injection), on the risk of multiple births., Study Design: We utilized the health care utilization databases of the Lombardy region to identify births resulting from MAR between 2007 and 2022. We gathered data on the total number of multiple births and calculated the prevalence rate by dividing the number of multiples by the total number of births. To examine the temporal trend in the proportion of multiple births after MAR over time, a linear regression model was employed separately for different types of techniques and in strata of maternal age., Results: A total of 30,900 births after MAR were included; 4485 (14.5 %) first line treatments and 26,415 (85.5 %) IVF techniques. Overall, 4823 (15.6 %) multiple births were identified. The frequency of multiple births over the study period decreased from 22.0 % in 2007 to 8.7 % in 2022 (p < 0.01). Multiple births from first line treatments were stable ranging from 13.5 % in 2007-2008 to 12.0 % in 2021-2022 (p = 0.29). Multiple births from IVF procedures decreased from 23.8 % in 2007-2008 to 8.4 % in 2021-2022 (p < 0.01). Stratifying for maternal age (i.e. < 35 and ≥ 35 years), the trends remained consistent., Conclusions: The reduction in multiple births has been influenced by changes in IVF strategy and procedures. The decline has been gradual but steady since 2009, when a law restricting embryo freezing was repealed in Italy. In contrast, the proportion of multiple births resulting from first line treatments has remained constant over time. Despite declining, multiple births from MAR remained about one order of magnitude higher than those from spontaneous pregnancies., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Edgardo Somigliana reports grants from Ferring, grants and personal fees from Merck-Serono, grants and personal fees from Theramex, personal fees from Gedeon-Richter, outside the submitted work. Giovanni Corrao received research support from the European Community (EC), the Italian Agency of Drugs (AIFA), and the Italian Ministry for University and Research (MIUR). He took part in a variety of projects that were funded by pharmaceutical companies (i.e. Novartis, GSK, Roche, AMGEN and BMS). He also received honoraria as a member of the advisory board to Roche. The other authors declare that they have no conflicts of interest to disclose., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

This present study investigated the parental characteristics of multiple births using national birth data in Japan. This study included birth data from Vital Statistics: Occupational and Industrial Aspects every five fiscal years from 1995 to 2020. The multiple birth rates were defined as the number of live-birth deliveries with multiple fetuses (e.g., twins, triplets) per total live-birth deliveries. Parental ages, nationalities, occupations and household occupation (occupation of the top earner of the household) were considered as parental characteristics. The multiple birth rates were calculated based on parental characteristics for each year, and a log-binomial regression model was used to assess the association between parental characteristics and multiple births. The multiple birth rate for Japanese mothers consistently exceeded that for non-Japanese mothers over the years, and the rate increased progressively from manual workers to lower non-manual workers and then to upper non-manual workers for both maternal and paternal occupations. The regression results indicated that the risk ratio (RR) for multiple births among non-Japanese mothers was significantly lower than that among Japanese mothers. Moreover, concerning household occupation, the RRs of self-employed individuals, full-time employees at smaller companies, others, and the unemployed were significantly lower than those of full-time employees at larger companies. Furthermore, the RRs of lower non-manual and manual workers were significantly lower than those of upper non-manual workers in maternal and paternal occupations. The results suggested an association between multiple births and parental socioeconomic status in Japan.

Research Question: What are the trends in patient characteristics, effectiveness and safety of assisted reproductive technology (ART) performed in Latin America over the past three decades, as well as the detailed outcomes of procedures initiated in 2018?, Design: Retrospective collection of multinational data including epidemiology and outcomes of ART performed between 1990 and 2018., Results: Over these 30 years we report 955,117 initiated cycles, 191,191 deliveries and 238,045 live births. In 1990, 66.5% of women were ≤34 years and 8.7% ≥40 years; in 2018, 26.4% of women were ≤34 years and 32.0% were ≥40 years. In 1990, 60.4% of transfers included ≥3 embryos, falling to 13.5% in 2018, and single embryo transfer (SET) increased from 13.8% to 30.4% between 1990 and 2018. Delivery rate per fresh transfer increased from approximately 17% in the 1990s to 25% in 2018, with a meaningful drop in high-order multiples, from 5-9% in the 1990s to 0.4% in 2018. This drop is associated with increasing use of frozen embryo transfer (FET) (57% in 2018) compared with 10% in 2000. In 2018, delivery rate in FET was 28.3%, reaching 31.2% in freeze-all cycles; and the cumulative live birth rate (fresh + FET) was 41.9%. Elective SET also increased, from 0.9% in 2010 to 10% in 2018. The delivery rate in elective SET (31.7%) was only 5.4% lower than elective double embryo transfer (DET) (37.1%); however, multiple births increased from 2.1% to 25.5% twins and 0.4% triplets in elective DET., Conclusion: The Latin American Registry of Assisted Reproduction (RLA) celebrates 30 years of voluntary reporting from a total of nearly 200 centres in 15 countries. This South-South Cooperation network has proven to be an efficient and safe system for technological transfer and regional growth., (Copyright © 2021 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Objectives-This report presents 2019 data on U.S. births according to a wide variety of characteristics. Trends in fertility patterns and maternal and infant characteristics are described and interpreted. Methods-Descriptive tabulations of data reported on the birth certificates of the 3.75 million births that occurred in 2019 are presented. Data are presented for maternal age, livebirth order, race and Hispanic origin, marital status, tobacco use, prenatal care, source of payment for the delivery, method of delivery, gestational age, birthweight, and plurality. Selected data by mother's state of residence and birth rates by age are also shown. Trend data for 2010 through 2019 are presented for selected items. Trend data by race and Hispanic origin are shown for 2016-2019. Results-A total of 3,747,540 births were registered in the United States in 2019, down 1% from 2018. The general fertility rate declined from 2018 to 58.3 births per 1,000 women aged 15-44 in 2019. The birth rate for females aged 15-19 fell 4% between 2018 and 2019. Birth rates declined for women aged 20-34 and increased for women aged 35-44 for 2018-2019. The total fertility rate declined to 1,706.0 births per 1,000 women in 2019. Birth rates declined for both married and unmarried women from 2018 to 2019. The percentage of women who began prenatal care in the first trimester of pregnancy rose to 77.6% in 2019; the percentage of all women who smoked during pregnancy declined to 6.0%. The cesarean delivery rate decreased to 31.7% in 2019 (Figure 1). Medicaid was the source of payment for 42.1% of all births in 2019. The preterm birth rate rose for the fifth straight year to 10.23% in 2019; the rate of low birthweight was essentially unchanged from 2018 at 8.31%. Twin and triplet and higher-order multiple birth rates both declined in 2019 compared with 2018., (All material appearing in this report is in the public domain and may be reproduced or copied without permission; citation as to source, however, is appreciated.)

Multiple births (twins or higher order multiples) are increasing in developed countries and may present higher risk for cerebral palsy (CP). However, few studies can reliably investigate trends over time because these outcomes are relatively rare., Objective: We pooled data from European CP registers to investigate CP birth prevalence and its trends among single and multiple births born between 1990 and 2008., Design: Population cohort study., Setting: 12 population-based registers from the Surveillance of Cerebral Palsy in Europe collaboration., Participants: 4 446 125 single and multiple live births, of whom 8416 (0.19%) had CP of prenatal or perinatal origin., Main Outcomes: CP diagnosis ascertained in childhood using harmonised methods; CP subtype; Motor impairment severity among CP cases., Results: The rate of multiple births increased from 1990. Multiples displayed higher risk for CP (RR=4.27, 95% CI 4.00 to 4.57). For singletons and multiples alike, risk for CP was higher among births of lower gestational age (GA) or birth weight (BW). However, CP birth prevalence declined significantly among very preterm (<32 weeks) and very low BW (<1500 g) multiples. Singletons and multiples with CP displayed similar severity of motor impairment., Conclusions: Between 1990 and 2008, CP birth prevalence decreased steadily among multiples with low GA or BW. Furthermore, multiples with CP display similar profiles of severe motor impairment compared with CP singletons. Improvements in management of preterm birth since the 1990s may also have been responsible for providing better prospects for multiples., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: To determine whether outcomes among infants with very low birth weight (VLBW) vary according to the birthplace (Japan or California) controlling for maternal ethnicity., Study Design: Severe intraventricular hemorrhage (IVH) and mortality were ascertained for infants with VLBW born at 24-29 weeks of gestation during 2008-2017 and retrospectively analyzed by the country of birth for mothers and infants (Japan or California)., Results: Rates of severe IVH, mortality, or combined IVH/mortality were lower in the 24 095 infants born in Japan (5.1%, 5.0%, 8.8% respectively) compared with infants born in California either to 157 mothers with Japanese ethnicity (12.5%, 9.7%, 17.8%) or to a comparison group of 6173 non-Hispanic white mothers (8.4%, 8.8%, 14.6%). ORs for adverse outcomes were increased for infants born in California to mothers with Japanese ethnicity compared with infants born in Japan for severe IVH (OR, 3.31; 95% CI, 1.93-5.68), mortality (3.73; 95% CI, 2.03-6.86), and the combined outcome (3.26; 95% CI, 2.02-5.27). The odds of these outcomes also were increased for infants born in California to non-Hispanic white mothers compared with infants born in Japan. Outcomes of infants born in California did not differ by Japanese or non-Hispanic white maternal ethnicity., Conclusions: Low rates of severe IVH and mortality for infants with VLBW born in Japan were not seen in infants born in California to mothers with Japanese ethnicity. Differences in systems of regional perinatal care, social environment, and the quality of perinatal care may partially account for these differences in outcomes., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: There are limited data available on the survival and early complications of preterm infants with less than 500 g birthweight. To estimate the outcomes for these infants, it is important for caregivers to be aware of perinatal factors that may affect survival., Objectives: We assessed the mortality and certain early complications of preterm infants born with less than 500 g in Hungary between 2006 and 2015., Methods: We reviewed data of 486 infants from the database of the Hungarian Central Statistical Office and in parallel of 407 infants from the "NICU database." The study period was divided into two epochs: 2006-2010 and 2011-2015., Results: The survival was 27.1% in the first epoch and 39.1% in the second epoch, and the incidence of early complications was slightly higher in the second epoch. In the surviving group (first and second epoch combined), gestational age (25.1 vs 23.7 weeks), birthweight (458 vs 447 g) antenatal steroid treatment (66.3% vs 52.3%), surfactant therapy (95.1% vs 84.3%), median Apgar scores (6 vs 3 and 8 vs 5 at 1 and 5 minutes, respectively) and proportion of caesarean delivery (89.3% versus 68.5%) were higher than in the non-surviving group (first and second epoch combined). The proportion of multiple births was lower in the surviving group (15.7% vs 33.4%)., Conclusions: Survival of infants with less than 500 g improved between 2006-2010 and 2011-2015 in Hungary. The slightly higher occurrence of early complications might be associated with improving survival., (© 2019 The Authors. Paediatric and Perinatal Epidemiology Published by John Wiley & Sons Ltd.)

It is desirable for twin researchers to be aware of the needs and concerns of families of multiples and provide participants with appropriate and useful feedback and advice based on scientific evidence. Our most recent database on families with twins throughout Japan is based on a questionnaire survey conducted in 2016. Mailed questionnaires, consisting of over 500 items, were used to collect the basic data. The response rate was 38% (566/1478). This is part of a nationwide study designed to assess the long-term effect of perinatal conditions on mothers of multiples. Its aim was to study the growth and development of multiples in childhood, and for the creation of a multifetal mother and child health handbook, and to conduct a genetic epidemiologic study to test the developmental origin of health and disease hypothesis. One of the ultimate aims of this research was to provide evidence-based information on parenting of multiples for families with multiples.

The new West Japan Twins and Higher Order Multiple Births Registry was established by recruiting young twins and multiple births and by referrals from public health centers in the 1990s. The participants included in the survey comprised over 7800 twins and 4241 higher order multiples, and their families. Specifically, the present registry contains one of the largest triplet samples in the world. For these twins and multiples, data on year of delivery, mode of delivery, gestational age, intrapartum complications, longitudinal physical measures, motor milestones, cerebral palsy and feeding methods were obtained from records in the Maternal and Child Health Handbooks and schools. Participating mothers were asked to indicate family structure, parental educational history, maternal sleeping time, maternal health condition, maternal and paternal age at multiple delivery, complications during pregnancy, handedness of multiples and age at menarche of multiples. However, the zygosity differed among the various collaborating public health centers according to factors such as the time of investigation. Follow-up questionnaires have been mailed out every 3-4 years for longitudinal studies. This article describes the goals of this registry, recruitment of multiples and the focus of the study. The goals of this registry are not only to conduct research on human genetics and maternal and child health, but also to contribute to providing appropriate information for families with multiples.

Objectives-This report presents 2018 data on U.S. births according to a wide variety of characteristics. Trends in fertility patterns and maternal and infant characteristics are described and interpreted. Methods-Descriptive tabulations of data reported on the birth certificates of the 3.79 million births that occurred in 2018 are presented. Data are presented for maternal age, live-birth order, race and Hispanic origin, marital status, tobacco use, prenatal care, source of payment for the delivery, method of delivery, gestational age, birthweight, and plurality. Selected data by mother's state of residence and birth rates by age also are shown. Trend data for 2010 through 2018 are presented for selected items. Trend data by race and Hispanic origin are shown for 2016-2018. Results-3,791,712 births were registered in the United States in 2018, down 2% from 2017. Compared with rates in 2017, the general fertility rate declined to 59.1 births per 1,000 women aged 15-44. The birth rate for females aged 15-19 fell 7% in 2018. Birth rates declined for women aged 20-34 and increased for women aged 35-44. The total fertility rate declined to 1,729.5 births per 1,000 women in 2018. Birth rates for both married and unmarried women declined from 2017 to 2018. The percentage of women who began prenatal care in the first trimester of pregnancy rose to 77.5% in 2018; the percentage of all women who smoked during pregnancy declined to 6.5%. The cesarean delivery rate decreased to 31.9% in 2018 following an increase in 2017. Medicaid was the source of payment for 42.3% of all 2018 births, down 2% from 2017. The preterm birth rate rose for the fourth straight year to 10.02% in 2018; the rate of low birthweight was unchanged at 8.28%. Twin and triplet and higher-order multiple birth rates declined in 2018 (Figure 1)., (All material appearing in this report is in the public domain and may be reproduced or copied without permission; citation as to source, however, is appreciated.)

Competing Interests: Competing interests: None declared.

Introduction: Multiple pregnancy has increased in prevalence in the last few years, which could lead to more foetal and maternal morbidity issues. The aim of this study is to describe the trend of multiple pregnancy deliveries in Castilla y León during the last 13years and the subsequent impact on foetal and maternal health., Material and Methods: Data was collected from the hospital discharge reports registered in the Regional Health-care database (SACYL: Health care in Castilla y León) between 2001 and 2013. A cross sectional descriptive study was conducted, including trend analysis with log-linear joint point model, a rhythm metric study, as well as a risk assessment with multivariate analysis., Results: A pronounced upward trend was observed in the proportion of multiple deliveries in this time period, compared to single ones, with an annual percentage change of 3.4% (95% CI: 2.5-4.4). Multiple pregnancy was significantly correlated with advanced maternal age, abnormal glucose tolerance, dystocia and caesarean section delivery, premature birth, foetal malposition, foetal macrosomia, stillbirth, in vitro fertilisation, and hypertensive episodes of pregnancy. In vitro fertilization showed a 9.3 fold increased risk in multiple pregnancy (95% CI: 7.4-11.5), with maternal age increasing the risk up to 5% per year of age (OR: 1.05: 95%CI: 1.04-1.05). No seasonal rhythm was observed in multiple deliveries compared with single ones., Conclusion: Multiple pregnancy has experienced a continuous increase, with no seasonal trend, and is associated with the increase in assisted reproductive technology and advanced maternal age. This involves more problems regarding foetal and maternal morbidity and mortality., (Copyright © 2018 Asociación Española de Pediatría. Publicado por Elsevier España, S.L.U. All rights reserved.)

Background: Brazil experienced important progress in maternal and child health in recent decades. We aimed at describing secular trends as well as socioeconomic and ethnic inequalities in reproductive history indicators (birth spacing, previous adverse perinatal outcome, parity and multiple births) over a 33-year span., Methods: Four population-based birth cohort studies included all hospital births in 1982, 1993, 2004 and 2015 in Pelotas, Southern Brazil. Information on reproductive history was collected through interviews. Indicators were stratified by family income quintiles and skin colour. Absolute and relative measures of inequality were calculated., Results: From 1982 to 2015, the proportion of primiparae increased from 39.2% to 49.6%, and median birth interval increased by 23.2 months. Poor women were more likely to report short intervals and higher parity, although reductions were observed in all income and ethnic groups. History of previous low birthweight was inversely related to income and increased by 7.7% points (pp) over time-more rapidly in the richest (12.1 pp) than in the poorest quintile (0.4 pp). Multiple births increased from 1.7% to 2.7%, with the highest increase observed among the richest quintile and for white women (220% and 70% increase, respectively). Absolute and relative income and ethnic-related inequalities for short birth intervals increased, whereas inequalities for previous low birthweight decreased over time., Conclusions: In this 33-year period there were increases in birth intervals, multiple births and reports of previous low-birthweight infants. These trends may be explained by increased family planning coverage, assisted reproduction and a rise in preterm births, respectively. Our results show that socioeconomic and ethnic inequalities in health are dynamic and vary over time, within the same location., (© The Author(s) 2019. Published by Oxford University Press on behalf of the International Epidemiological Association.)

Objectives-This report presents 2017 data on U.S. births according to a wide variety of characteristics. Trends in fertility patterns and maternal and infant characteristics are described and interpreted. Methods-Descriptive tabulations of data reported on the birth certificates of the 3.86 million births that occurred in 2017 are presented. Data are presented for maternal age, livebirth order, race and Hispanic origin, marital status, tobacco use, prenatal care, source of payment for the delivery, method of delivery, gestational age, birthweight, and plurality. Selected data by mother's state of residence and birth rates by age also are shown. Trend data for 2010 to 2017 are presented for selected items. Trend data by race and Hispanic origin are shown for 2016 and 2017. Results- A total of 3,855,500 births were registered in the United States in 2017, down 2% from 2016. Compared with rates in 2016, the general fertility rate declined to 60.3 births per 1,000 women aged 15-44. The birth rate for females aged 15-19 fell 7% in 2017. Birth rates declined for women in their 20s and 30s but increased for women in their early 40s. The total fertility rate declined to 1,765.5 births per 1,000 women in 2017. Birth rates for both married and unmarried women declined from 2016 to 2017. The percentage of women who began prenatal care in the first trimester of pregnancy rose to 77.3% in 2017; the percentage of all women who smoked during pregnancy declined to 6.9%. The cesarean delivery rate increased to 32.0% following 4 years of declines. Medicaid was the source of payment for 43.0% of all births in 2017, up 1% from 2016. The preterm birth rate rose for the third straight year, as did the rate of low birthweight. Twin and triplet and higher-order multiple birth rates were essentially stable in 2017., (All material appearing in this report is in the public domain and may be reproduced or copied without permission; citation as to source, however, is appreciated.)

Objective: To establish the annual and cumulative multiyear contribution of delayed childbearing to the national plural birth excess., Methods: Using publicly available national birth data reported by the National Center for Health Statistics, we estimated the contribution of delayed childbearing to the national plural birth excess through 2016. To this end, the observed as well as the maternal age- and race-adjusted national plural birth rates were assessed before (1949-1966; n=71,570,717) and during (1971-2016; n=166,817,655) the assisted reproduction era. Comparable estimates through 2025 relied on simulated projections., Results: The relative risk estimates of unassisted plural births by maternal age before the assisted reproduction era (1949-1966) proved unimodal and race-dependent. The risk of unassisted plural births in 35- to 39-year-old black women proved 2.75-fold higher than that of 15- to 19-year-old counterparts (39.81/1,000 to 14.48/1,000; 95% CI 2.67-2.83). A 2.47-fold risk increment was noted for comparably aged white women (28.76/1,000 to 11.63/1,000; 95% CI 2.43-2.52). Similar age-dependent risk increments were obtained for twin and higher order births. An increasingly prominent delayed childbearing trend during the assisted reproduction era (1971-2016) gave rise to 255,964 (95% CI 134,746-375,581) and 66,271 (95% CI 34,099-96,197) unassisted plural births by white and black women, respectively. In 2016 alone, delayed childbearing accounted for 24% (95% CI 15-32%) and 38% (95% CI 28-47%) of the national plural birth excess for white and black women, respectively. By 2025, delayed childbearing could account for as much as 46% (95% CI 32-60%) and 40% (95% CI 30-53%) of the national plural birth excess for white and black women, respectively., Conclusion: Delayed childbearing, a growing contributor to the national plural birth excess previously solely ascribed to assisted reproduction, warrants greater consideration in future clinical, analytic, and policy deliberations as well as in individual family planning decisions.

In the 19th century, a series of international statistical congresses began that were important for population studies, including twin research. The introduction of common rules for the national demographic registers enabled scientists to contribute to the genesis of statistical research. The congress in St. Petersburg in 1872, in particular, focused on the movements of the population, and how they should be registered. Among the facts to be recorded were in multiple births, the sex and number of children born alive or still-born, whether legitimate or illegitimate, and the age of the mother at the date of the births. During the history of twin research, Hellin's law has played a central role because it is an approximately correct association between the rates of multiple maternities. It has been mathematically proven that Hellin's law does not hold as a general rule. Analyses show divergences from the law that are difficult to explain and/or eliminate. Varying improvements of this law have been proposed. The majority of all studies of Hellin's law are based on empirical rates of multiple maternities, ignoring random errors. Such studies can never confirm the law, but only identify errors with respect to Hellin's law that are too large to be characterized as random. It is of particular interest to note and explain why the rates of higher multiple maternities are sometimes too high or too low when Hellin's law is used as a benchmark. Studies have shown that there were investigators before Hellin who have contributed substantially to Hellin's law. In this article, we re-examine some old data sets and contributions in which Hellin's law has been evaluated and also analyze recent data.

Aim: To calculate the birth prevalence of cerebral palsy (CP) after assisted reproductive technology (ART) and compare the clinical outcomes of children with CP after ART or natural conception., Method: This cohort study used linked CP and ART register data from live births in Western Australia (1994-2002). Birth prevalence was calculated and data analysed using descriptive statistics and logistic regression. It was adjusted for confounding variables and stratified by plurality and gestational age., Results: In total, 211 660 live births were included; prevalence of CP was increased in children born after ART (7.2/1000 live births compared with naturally conceived births, 2.5/1000). Odds of CP were doubled for singletons; when stratified by gestational age odds were only increased in the under 32-week group. Prevalence of CP was increased in ART (9.9/1000 live births) and naturally conceived twins (8.4/1000 live births). Clinical outcomes were similar between ART and naturally conceived children., Interpretation: The birth prevalence of CP is increased two-fold after ART. After stratification for gestational age and plurality, residual risk remains in singletons born very preterm. Birth prevalence of CP will be tracked over time to identify any impact of changes to clinical practice., What This Paper Adds: In Western Australia, assisted reproductive technology (ART) increases birth prevalence of cerebral palsy (CP), mediated mostly by preterm and multiple births. Preterm birth alone does not account for the doubled odds of CP for ART singletons born very preterm. Clinical outcomes are similar between ART and naturally conceived children with CP., (© 2017 Mac Keith Press.)

This report presents 2016 data on U.S. births according to a wide variety of characteristics. Trends in fertility patterns and maternal and infant characteristics are described and interpreted.Descriptive tabulations of data reported on the birth certificates of the 3.95 million births that occurred in 2016 are presented. Data are presented for maternal age, live-birth order, race and Hispanic origin, marital status, tobacco use, prenatal care, source of payment for the delivery, method of delivery, gestational age, birthweight, and plurality. Selected data by mother's state of residence and birth rates by age also are shown. Trend data for 2010-2016 are presented for selected items. A total of 3,945,875 births were registered in the United States in 2016, down 1% from 2015. Compared with rates in 2015, the general fertility rate declined to 62.0 per 1,000 women aged 15-44. The birth rate for females aged 15-19 fell 9% in 2016. Birth rates declined for women in their 20s but increased for women intheir 30s and early 40s. The total fertility rate declined to 1,820.5 births per 1,000 women in 2016. The birth rate for unmarried women declined, while the rate for married women increased. More than three-quarters of women began prenatal care in the firsttrimester of pregnancy (77.1%) in 2016, while 7.2% of all women smoked during pregnancy. The cesarean delivery rate declined for the fourth year in a row. Medicaid was the source of payment for 42.6% of all 2016 births. The preterm birth rate rose for the second straight year, and the rate of low birthweight increased 1%. Twin and triplet and higher-order multiple birth rates declined, although the changes were not statistically significant., (All material appearing in this report is in the public domain and may be reproduced or copied without permission; citation as to source, however, is appreciated.)

Background: Congenital cytomegalovirus (cCMV) infection is an important cause of hearing loss and neurodevelopment delay. While data on vertical transmission and neonatal outcome after singleton pregnancy with cCMV are well established, only scarce reports have addressed cCMV in multiple birth pregnancies. Furthermore, no studies have yet compared the outcome after birth and long-term follow-up of children with cCMV born after a singleton versus multiple pregnancies., Methods: Infant outcome after birth of symptomatic versus asymptomatic infection was compared for infants born with cCMV after multiple (study group) and singleton (control group) pregnancies in a 1:2 ratio., Results: Of 508 infants diagnosed with cCMV, 25 (4.9%) were born after a multiple pregnancy. Children in the study and control groups did not differ in terms of specific prenatal CMV investigations including amniocentesis and brain magnetic resonance imaging studies. However, prematurity rates were significantly higher in the study compared with control group (52% vs. 4%, P < 0.001). There was a higher rate of symptomatic cCMV infection in the study group than in the controls (48% vs. 14%, P < 0.001). Hearing impairment at birth was also more frequent in the study group (32% vs. 8%, P = 0.016). A long-term follow-up demonstrated that children in the study group had higher rates of neurologic sequelae (hearing impairment or neurodevelopmental delay) compared with children in the control group (20% vs. 4%, P = 0.016)., Conclusions: Infants with cCMV born after multiple birth pregnancies are born earlier and have a higher risk of symptomatic disease at birth and worse long-term neurologic outcome than those born after a singleton pregnancy. This important group of children warrants meticulous prenatal and postnatal care.

Objectives: The aim of this study is to describe the experience and outcome of higher order multiple (HOM) births in a private tertiary health facility in Nigeria., Materials and Methods: This was a retrospective review of records of HOM over 3 years in a private tertiary health facility in Nigeria. Relevant data on HOM births were extracted from both the patients' case notes, admission registers and maternity ward and delivery records of the hospital using a predesigned pro forma. Data were analyzed using Statistical Package for Social Sciences Version 22.0., Results: The prevalence of HOM births was 0.72% of 1950 births over the 3 years study period; while for triplets, quadruplets, and quintuplets were 0.56%, 0.1% and 0.05%, respectively. The mean gestational age was 32 ± 3 weeks, and all except three sets of triplets were by Assisted Reproductive Technology (ART). Respiratory distress syndrome, neonatal jaundice, and neonatal sepsis accounted for more than 80% of the neonatal complications noted in HOM births. However, there was no significant difference between neonatal survival of HOM as compared to twin deliveries, P = 0.08., Conclusion: HOM is becoming increasingly common in Nigeria. The strongest risk factor is ART, and neonatal complications are common reinforcing the need to streamline ART protocols in Nigeria.

Belgian legislation limiting the number of embryos for transfer has been shown to result in a 50% reduction of the multiple live birth rate (MLBR) per cycle without having a negative impact on the cumulative delivery rate per patient within six cycles or 36 months. The objective of the current study was to evaluate the cost saving associated with a 50% reduction in MLBR. A retrospective cost analysis was performed of 213 couples, who became pregnant and had a live birth after one or more assisted reproductive technology treatment cycles, and their 254 children. The mean cost of a singleton (n = 172) and multiple (n = 41) birth was calculated based on individual hospital invoices. The cost analysis showed a significantly higher total cost (assisted reproductive technology treatment, pregnancy follow-up, delivery, child cost until the age of 2 years) for multiple births (both children: mean €43,397) than for singleton births (mean: €17,866) (Wilcoxon-Mann-Whitney P < 0.0001). A 50% reduction in MLBR resulted in a significant cost reduction related to hospital care of 13%., (Copyright © 2017 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

Multinational data on assisted reproduction techniques (IVF and intractytoplasmic sperm injection [ICSI], frozen embryo transfer, oocyte donation, preimplantation genetic diagnosis and fertility preservation) were collected from 159 institutions in 15 Latin American countries. A total of 41.34% of IVF-ICSI cycles were conducted in women aged 35-39 years and 23.35% in women aged 40 years and older. After removing freeze-all cases, delivery rate per oocyte retrieval was 25.05% for ICSI and 27.41% for IVF. Multiple births included 20.78% twins and 0.92% triplets and over. In oocyte donation, twins reached 28.93% and triplets 1.07%. Preterm deliveries reached 16.4% in singletons, 55.02% in twins and 76% in triplets. Perinatal mortality in 18,162 births was 23 per 1000 in singletons, 35 per 1000 in twins, and 36 per 1000 in high-order multiples. Elective single embryo transfer represented 2.63% of fresh transfers, with a 32.15% delivery rate per transfer. Elective double embryo transfer represented 23.74% of transfers, with a 41.03% delivery rate per transfer; 11,373 babies (62.6%) were singletons; 6398 (35.2%) twins, and 391 (2.2%), triplets and more. Given the effect of multiple births on prematurity, morbidity and perinatal mortality, reinforcing the existing trend of reducing the number of embryos transferred is mandatory., (Copyright © 2017 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

Background: The analysis of perinatal outcomes often involves datasets with some multiple births. These are datasets mostly formed of independent observations and a limited number of clusters of size two (twins) and maybe of size three or more. This non-independence needs to be accounted for in the statistical analysis. Using simulated data based on a dataset of preterm infants we have previously investigated the performance of several approaches to the analysis of continuous outcomes in the presence of some clusters of size two. Mixed models have been developed for binomial outcomes but very little is known about their reliability when only a limited number of small clusters are present., Methods: Using simulated data based on a dataset of preterm infants we investigated the performance of several approaches to the analysis of binomial outcomes in the presence of some clusters of size two. Logistic models, several methods of estimation for the logistic random intercept models and generalised estimating equations were compared., Results: The presence of even a small percentage of twins means that a logistic regression model will underestimate all parameters but a logistic random intercept model fails to estimate the correlation between siblings if the percentage of twins is too small and will provide similar estimates to logistic regression. The method which seems to provide the best balance between estimation of the standard error and the parameter for any percentage of twins is the generalised estimating equations., Conclusions: This study has shown that the number of covariates or the level two variance do not necessarily affect the performance of the various methods used to analyse datasets containing twins but when the percentage of small clusters is too small, mixed models cannot capture the dependence between siblings.

Purpose: To perform a systematic review and meta-analysis of reported estimates of adverse pregnancy outcomes among multiple births conceived with in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI)., Methods: PubMed, Google Scholar, Cochrane Libraries and Chinese databases were searched through May 2016 for cohort studies assessing adverse pregnancy outcomes associated with IVF/ICSI multiple births. Random-effects meta-analyses were used to calculate pooled estimates of adverse pregnancy outcomes and, where appropriate, heterogeneity was explored in group-specific analyses., Results: Sixty-four studies, with 60,210 IVF/ICSI multiple births and 146,737 spontaneously conceived multiple births, were selected for analysis. Among IVF/ICSI multiple births, the pooled estimates were 51.5% [95% confidence interval (CI): 48.7-54.3] for preterm birth, 12.1% (95% CI: 10.4-14.1) for very preterm birth, 49.8% (95% CI: 47.6-52.0) for low birth weight, 8.4% (95% CI: 7.1-9.9) for very low birth weight, 16.2% (95% CI: 12.9-20.1) for small for gestational age, 3.0% (95% CI: 2.5-3.7) for perinatal mortality and 4.7% (95% CI: 4.0-5.6) for congenital malformations. When the data were restricted to twins, the pooled estimates also showed a high prevalence of adverse outcomes. There was a similar prevalence of poor outcomes among multiple births conceived with IVF/ICSI and naturally (all P ≥ 0.0792). Significant differences in different continents, countries, and income groups were found., Conclusions: The IVF/ICSI multiple pregnancies have a high prevalence of adverse pregnancy outcomes. However, population-wide prospective adverse outcomes registries covering the entire world population for IVF/ICSI pregnancies are needed to determine the exact perinatal prevalence.

In 2015, there was an increase in the number of births in South Dakota compared to the previous year. Further, the state's 2014 birth rate (14.4) exceeded the 12.5 rate observed nationally for this year. Similar to national trends, one-quarter of South Dakota newborns represent minority populations. The infant mortality rate of 7.3 for the state in 2015 was 24 percent higher than the 2014 rate. Analyses of factors that contributed to this increase show that twice as many infants died of sudden unexpected infant death (SUID) in 2015 as has been observed in previous years. SUID was the cause of 30 percent of the state's infant deaths in 2015 versus 19 percent in 2014. Between 2011 and 2015, the SUID rate has been four times higher for minority than white infants. A discussion of strategies for the prevention of these deaths is presented., (Copyright© South Dakota State Medical Association.)

Objectives-This report presents 2015 data on U.S. births according to a wide variety of characteristics. Data are presented for maternal age, live-birth order, race and Hispanic origin, marital status, attendant at birth, method of delivery, period of gestation, birthweight, and plurality. Selected data by mother's state of residence and birth rates by age and race of father also are shown. Trends in fertility patterns and maternal and infant characteristics are described and interpreted. Methods-Descriptive tabulations of data reported on the birth certificates of the 3.98 million births that occurred in 2015 are presented. Results-In 2015, 3,978,497 births were registered in the United States, down less than 1% from 2014. The general fertility rate was 62.5 per 1,000 women aged 15-44, a decline of 1% from 2014. The birth rate for teenagers aged 15-19 fell 8% in 2015, to 22.3 per 1,000 females. Birth rates declined for women in their 20s but increased for women in their 30s and early 40s. The total fertility rate (estimated number of births over a woman's lifetime) declined to 1,843.5 births per 1,000 women in 2015. The birth rate for unmarried women declined for the seventh straight year to 43.5 per 1,000. The cesarean delivery rate declined for the third year in a row to 32.0%. The preterm birth rate increased slightly from 2014, to 9.63% in 2015, as did the rate of low birthweight (8.07% in 2015). The twin birth rate declined to 33.5 per 1,000; the triplet and higher-order multiple birth rate was down 9% to 103.6 per 100,000., (All material appearing in this report is in the public domain and may be reproduced or copied without permission; citation as to source, however, is appreciated.)

Key Findings: Data from the National Vital Statistics System •There were 3.978 million births in the United States in 2015, down less than 1% from 2014. •The 2015 U.S. general fertility rate (births per 1,000 women aged 15-44) was down 1% from 2014. •Birth rates dropped in 2015 to record lows among women under age 30 and rose for those aged 30-44. •The cesarean delivery rate declined to 32.0% of births in 2015; the preterm birth rate rose slightly to 9.63% from 2014 to 2015. This report presents several key demographic and maternal and infant health indicators using 2015 final birth data. Trends in general fertility rates, age-specific birth rates, cesarean and low-risk cesarean delivery, and preterm birth rates are presented. Data are from the national vital statistics birth files., (All material appearing in this report is in the public domain and may be reproduced or copied without permission; citation as to source, however, is appreciated.)

Clomiphene and assisted reproductive technologies (ART) are methods used to help subfertile couples become pregnant. ART has been reported to be associated with neural tube defects (NTDs) in offspring. To evaluate these associations, we studied mothers of 219 cases and 4,262 controls from the Slone Epidemiology Center Birth Defects Study (1993-2012) who were interviewed within 6 months after delivery about pregnancy events, including use of fertility treatments. We considered exposures to clomiphene (without ART) and ART during the periconceptional period. Logistic regression models were used to calculate adjusted odds ratios and 95% confidence intervals, controlling for education and study center. We observed elevated adjusted odds ratios of 2.1 (95% confidence interval: 0.9, 4.8) and 2.0 (95% confidence interval: 1.1, 3.6) for clomiphene and ART exposure, respectively. We performed a mediation analysis to assess whether the observed elevated NTD risk was mediated through multiple births. For clomiphene exposure without ART use, the direct effect estimate of the adjusted odds ratio (aORDE) was 1.7 and the indirect effect estimate (aORIE) was 1.4. Conversely, for ART exposure, the aORDE was 0.9 and the aORIE was 2.5. Our findings suggest that relatively little of the clomiphene-NTD association is mediated through the pathway of multiple births, while the ART-NTD association was explained by the multiple-births pathway., (© The Author 2016. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Parkinson's disease (PD) may take decades to develop and early life exposures such as infection may be important. However, few epidemiological studies have evaluated early life risk factors in relation to PD risk. We therefore examined such associations in a prospective analysis of 3 545 612 individuals born in Sweden between 1932 and 1970 without PD on January 1, 2002. Incident PD cases were identified using the Swedish Patient Register during 2002-2010. Information on sibship size, number of older and younger siblings, multiple births, parental age, birth month and season was obtained from the Swedish Multi-Generation Register. Monthly data on national burden of influenza-like illness during 1932-1970 were obtained from the Swedish Public Health Agency. Hazard ratios with 95% confidence intervals (CI) were estimated using Cox proportional hazards regression. During the follow-up, 8779 incident PD cases were identified. As expected, older age, male sex, parental occupation as farmers, and family history of PD were associated with higher PD risk. Overall, early life factors, including flu burden in the year of birth, were not associated with PD risk, although we did find a lower PD risk among participants with older siblings than those without (HR = 0.93, 95%CI: 0.89, 0.98). Our study therefore provided little support for important etiological contributions of early life factors to the PD risk late in life. The finding of a lower PD risk among individuals with older siblings will need confirmation and further investigation.

Key Findings: Data from the National Vital Statistics System •The triplet and higher-order birth rate declined 41% from 1998 to 2014, or from about 1 in every 515 births in 1998 to one in every 880 births in 2014. •Triplet and higher-order birth rates were down by about 50% or more for women aged 25 and over. Rates were essentially unchanged for women under 25. •The largest declines in triplet and higher-order birth rates by race and Hispanic origin for 1998-2014 were for non-Hispanic white women, down 46% compared with a 15% decline for Hispanic women, and essentially no change for non-Hispanic black women. •Triplet and higher-order birth rates were down from 1998-2000 to 2012-2014 in 42 states; declines of more than 50% were observed in 7 states., (All material appearing in this report is in the public domain and may be reproduced or copied without permission; citation as to source, however, is appreciated.)

Background: The occurrence of multiple births has been recognized as a risk factor for child maltreatment. However, few population-based studies have examined the relationship between multiple births and child maltreatment. This study aimed to evaluate the degree of risk of child maltreatment among singletons and multiple births in Japan and to identify factors associated with increased risk., Methods: Using population-based data, we analyzed the database of records on child maltreatment and medical checkups for infants aged 1.5 years filed at Nishinomiya City Public Health Center between April 2007 and March 2011. To protect personal information, the data were transferred to anonymized electronic files for analysis., Results: After adjusting by logistic regression for each associated factor and gestation number, multiples themselves were not associated with the risk of child maltreatment. However, compared with singletons, multiples had a significantly higher rate of risk factors for child maltreatment, including low birth weight and neural abnormality. Moreover, compared with mothers of singleton, mothers of twins had a significantly higher rate of poor health, which is a risk factor of child maltreatment., Conclusion: Multiples were not associated with the risk of child maltreatment. However, compared with singletons, multiples and their mothers had a significantly higher rate of risk factors of child maltreatment.

Objective: We sought to quantify the risk of multiple births associated with the use of different modalities of medically assisted reproduction., Study Design: We conducted a case-control study using a birth cohort from 2006 through 2009. This cohort was built with the linkage of data obtained by a self-administered questionnaire and medical, hospital, pharmaceutical, birth, and death databases in Quebec. Cases were pregnancies resulting in multiple live births (International Classification of Diseases, Ninth Revision/International Statistical Classification of Diseases, 10th Revision codes). Each case was matched, on maternal age and year of delivery, with 3 singleton pregnancies (controls) randomly selected among all Quebec singleton pregnancies. Data on the use of different fertility treatments were collected by a self-administered questionnaire. Multiple logistic regression models, adjusted for body mass index, number of previous live births, ethnicity, family income, place of residence, marital status, subfertility, reduction of embryos, diabetes, metformin treatment, folic acid supplementation, and lifestyle factors, were used to calculate the odds ratios (ORs) and confidence intervals (CIs). We evaluated the associations between each type of fertility treatment (ovarian stimulators used alone, intrauterine insemination [IUI] used with ovarian stimulation, and assisted reproductive technologies [ART]) and the risk of multiple births., Results: A total of 1407 cases of multiple births and 3580 controls were analyzed. More than half of multiple births following medically assisted reproduction (53.6%) occurred among women having used ovarian stimulation with or without IUI. The use of ovarian stimulators alone and IUI with ovarian stimulation increase the risk of multiple births (adjusted OR, 4.5; 95% CI, 3.2-6.4; and adjusted OR, 9.32; 95% CI, 5.60-15.50, respectively) compared to spontaneous conception. The use of invasive ART was associated with a greatly increased risk of multiple births. Among only the 465 women who used medically assisted reproduction for conception, the use of IUI with ovarian stimulation was associated with an increased risk of multiple births (adjusted OR, 1.98; 95% CI, 1.12-3.49) when compared to ovarian stimulators used alone. Invasive ART were associated with an increased risk of multiple births (adjusted OR, 6.81; 95% CI, 3.72-12.49) when compared to ovarian stimulators used alone., Conclusion: Although the risk of multiple births associated with invasive ART can be decreased by elective implementing of single embryo transfer, special attention should be paid to the greatly increased risk associated with ovarian stimulation used alone or with IUI., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Objectives: This report presents 2013 period infant mortality statistics from the linked birth/infant death data set (linked file) by maternal and infant characteristics. The linked file differs from the mortality file, which is based entirely on death certificate data., Methods: Descriptive tabulations of data are presented and interpreted., Results: The U.S. infant mortality rate was 5.96 infant deaths per 1,000 live births in 2013, similar to the rate of 5.98 in 2012. The number of infant deaths was 23,446 in 2013, a decline of 208 infant deaths from 2012. From 2012 to 2013, infant mortality rates were stable for most race and Hispanic origin groups; declines were reported for two Hispanic subgroups: Cuban and Puerto Rican. Since 2005, the most recent high, the U.S. infant mortality rate has declined 13% (from 6.86), with declines in both neonatal and postneonatal mortality overall and for most groups. In 2013, infants born at 37–38 weeks of gestation (early term) had mortality rates that were 63% higher than for full-term (39–40 week) infants. For multiple births, the infant mortality rate was 25.84, 5 times the rate of 5.25 for singleton births. In 2013, 36% of infant deaths were due to preterm-related causes of death, and an additional 15% were due to causes grouped into the sudden unexpected infant death category., (All material appearing in this report is in the public domain and may be reproduced or copied without permission; citation as to source, however, is appreciated.)

Background: There is a global growing trend of preterm births and a decline trend of fetal deaths. Is there an impact of the decline of fetal mortality on the increase of preterm live births in State of Sao Paulo, Brazil?, Methods: The time trends were evaluated by gestational age through exponential regression analysis. Data analyzed included the fetal mortality ratio, proportion of preterm live births, fertility rate of women 35 years and over, prenatal care, mother's education, multiple births and cesarean section deliveries. A survival analysis was carried out for 2000 and 2010., Results: Preterm births showed the highest annual increase (3.2%) in the less than 28 weeks of gestation group and fetal mortality ratio decreased (7.4%) in the same gestational age group. There was an increase of cesarean section births and it was higher in the < 28 weeks group (6.1%). There was a decreased annual trend of mothers with inadequate prenatal care (6.1%) and low education (8.8%) and an increased trend in multiple births and fertility rates of women of 35 years and over. The variables were highly correlated to which other over time. In 2000, 8.2% of all pregnancies resulted in preterm births (0.9% in fetal deaths and 7.3% in live births). In 2010, the preterm birth increased to 9.4% (0.8% were preterm fetal deaths and 8.6% preterm live births)., Conclusions: The results suggest that 45.2% could be the maximum contribution of successful interventions to prevent a fetal death on the increase in preterm live births. This increasing trend is also related to changes of the women reproductive profile with the change of the women reproductive profile and access to prenatal care.

Objective: To evaluate the safety and efficacy of early rescue intracytoplasmic sperm injection (ICSI)., Design: Retrospective cohort study., Setting: Teaching hospital., Patient(s): There were 13,232 ovarian stimulation cycles (IVF, n = 9,631; ICSI, n = 2,871; early rescue ICSI, n = 730) that resulted in the delivery of 5,001 babies (IVF, n = 3,670; ICSI, n = 1,095; early rescue ICSI, n = 246) from August 2008 to August 2013., Intervention(s): Early rescue ICSI., Main Outcome Measure(s): Clinical pregnancy rates, neonatal outcomes, and congenital birth defects were analyzed., Result(s): The early rescue ICSI cycles did not seem to have a negative effect on the clinical pregnancy rate (43.42%) when IVF cycles (45.33%) were compared with ICSI cycles (44.39%). In the early rescue ICSI group, a total of 254 clinical pregnancies were achieved: 197 (33.67%) live births, 38 (6.49%) miscarriages, 2 (0.79%) induced abortions, 3 (1.18%) fetal deaths, and 4 pregnancies (1.57%) without completion at follow-up. Overall, the multiple gestations, the delivery method, mean gestational age, preterm deliveries, mean birth weight, and rate of congenital birth defects of the early rescue ICSI group were similar to those in the conventional IVF and ICSI groups., Conclusion(s): Early rescue ICSI had similar clinical pregnancy rates when compared with conventional IVF and ICSI, in addition to the delivery of healthy children. The clinical evidence from the early rescue ICSI group did not show an elevated rate of malformations. Early rescue ICSI seems to be a safe alternative method for individuals with total fertilization failure or near total fertilization failure when compared with conventional IVF treatment., (Copyright © 2015 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.)

Objective: The purpose of this study was to use a validated prediction model to examine whether single embryo transfer (SET) over 2 cycles results in live birth rates (LBR) comparable with 2 embryos transferred (DET) in 1 cycle and reduces the probability of a multiple birth (ie, multiple birth rate [MBR])., Study Design: Prediction models of LBR and MBR for a woman considering assisted reproductive technology developed from linked cycles from the Society for Assisted Reproductive Technology Clinic Outcome Reporting System for 2006-2012 were used to compare SET over 2 cycles with DET in 1 cycle. The prediction model was based on a woman's age, body mass index (BMI), gravidity, previous full-term births, infertility diagnoses, embryo state, number of embryos transferred, and number of cycles., Results: To demonstrate the effect of the number of embryos transferred (1 or 2), the LBRs and MBRs were estimated for women with a single infertility diagnosis (male factor, ovulation disorders, diminished ovarian reserve, and unexplained); nulligravid; BMI of 20, 25, 30, and 35 kg/m2; and ages 25, 35, and 40 years old by cycle (first or second). The cumulative LBR over 2 cycles with SET was similar to or better than the LBR with DET in a single cycle (for example, for women with the diagnosis of ovulation disorders: 35 years old; BMI, 30 kg/m2; 54.4% vs 46.5%; and for women who are 40 years old: BMI, 30 kg/m(2); 31.3% vs 28.9%). The MBR with DET in 1 cycle was 32.8% for women 35 years old and 20.9% for women 40 years old; with SET, the cumulative MBR was 2.7% and 1.6%, respectively., Conclusion: The application of this validated predictive model demonstrated that the cumulative LBR is as good as or better with SET over 2 cycles than with DET in 1 cycle, while greatly reducing the probability of a multiple birth., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Aim: To describe reduction as a method using van Manen's phenomenological hermeneutic research approach., Background: Reduction involves several levels that can be distinguished for their methodological usefulness. Researchers can use reduction in different ways and dimensions for their methodological needs., Data Sources: A study of Finnish multiple-birth families in which open interviews (n=38) were conducted with public health nurses, family care workers and parents of twins., Review Methods: A systematic literature and knowledge review showed there were no articles on multiple-birth families that used van Manen's method. Discussion The phenomena of the 'lifeworlds' of multiple-birth families consist of three core essential themes as told by parents: 'a state of constant vigilance', 'ensuring that they can continue to cope' and 'opportunities to share with other people'., Conclusion: Reduction provides the opportunity to carry out in-depth phenomenological hermeneutic research and understand people's lives. It helps to keep research stages separate but also enables a consolidated view. Social care and healthcare professionals have to hear parents' voices better to comprehensively understand their situation; they need further tools and training to be able to empower parents of twins., Implications for Research/practice: This paper adds an empirical example to the discussion of phenomenology, hermeneutic study and reduction as a method. It opens up reduction for researchers to exploit.

Objective: To evaluate assisted reproductive technology (ART) ET practices in the United States and assess the impact of these practices on multiple births, which pose health risks for both mothers and infants., Design: Retrospective cohort analysis using the National ART Surveillance System data., Setting: US fertility centers reporting to the National ART Surveillance System., Patient(s): Noncanceled ART cycles conducted in the United States in 2012., Intervention(s): None., Main Outcome Measure(s): Multiple birth (birth of two or more infants, at least one of whom was live-born)., Result(s): Of 134,381 ART transfer cycles performed in 2012, 51,262 resulted in live births, of which 13,563 (26.5%) were multiple births: 13,123 twin and 440 triplet and higher order births. Almost half (46.1%) of these multiple births resulted from the following four cycle types: two fresh blastocyst transfers among favorable or average prognosis patients less than 35 years (1,931 and 1,341 multiple births, respectively), two fresh blastocyst transfers among donor-oocyte recipients (1,532 multiple births), and two frozen/thawed ETs among patients less than 35 years (1,452 multiple births). More than half of triplet or higher order births resulted from the transfer of two embryos (52.5% of births among fresh autologous transfers, 67.2% of births among donor-oocyte recipient transfers, and 42.9% among frozen/thawed autologous transfers)., Conclusion(s): A substantial reduction of ART-related multiple (both twin and triplet or higher order) births in the United States could be achieved by single blastocyst transfers among favorable and average prognosis patients less than 35 years of age and donor-oocyte recipients., (Published by Elsevier Inc.)

Questions Under Study: The impact of assisted reproductive technology (ART) on Swiss demography was quantified. From 1993 to 2012 the number of deliveries, including multiples, generated by ART was compared with overall delivery numbers. Swiss experts in ART collaborated in a consensus to increase successful outcomes, to reduce the incidence of complications of ART and to validate recommendations through statistical review of available data., Methods: Data generated between 1993 and 2012 and published by the Federal Office of Statistics (BfS) were compared with the Swiss database on ART (FIVNAT-CH) as organised by the Swiss Society of Reproductive Medicine (SGRM). From these analyses a panel of Swiss experts in ART extracted recommendations to improve current practice, to prevent complications related to ART and to recommend changes in current Swiss legislation dealing with ART., Results: Since 1993 the age of women giving birth rose together with the number of women asking for ART. This demographic trend was reflected in a rise in the number of deliveries generated by ART (in 2012: 2.2%) and the proportion of multiple births (in 2012: 17.6%). The outcome of ART was most negatively influenced by the age of the treated patient. The number of retrieved oocytes decisively impacted the likelihood of delivery, the risk of multiple births and the incidence of ovarian hyperstimulation syndrome., Conclusions: Optimal ovarian stimulation should be designed for the retrieval of 10 to 15 oocytes per treatment. Swiss legislation should enable and stimulate a policy of elective single embryo transfer to avoid multiple births.

The study endeavored to assess the epidemiology, postnatal survival, and growth pattern of multiple births in Sub-Saharan Africa (SSA). It was based on the data of 25 demographic health surveys conducted in the subcontinent since 2008. The records of 213,889 children born in the preceding 59 months of the surveys were included. The multiple birth rate was computed as the number of multiple confinements per 1,000 births. Factors associated with multiple births were identified using logistic regression and their survival pattern was assessed using the Kaplan-Meier method. The multiple birth rate was 17.1 (95% confidence interval: 17.7-16.6) and showed considerable variation across the 25 countries included in the study. Odds of multiple births were significantly increased with advanced maternal age, parity, and maternal height but not with wealth index, age at first birth, and month of birth. At the end of the fourth year of age, the cumulative survival probability was as low as 0.77 in multiple births as compared to 0.93 in their counterparts. The odds of neonatal, infant and under-five mortality were 5.55, 4.39, and 3.72 times increased in multiple births, respectively. Multiple births tend to be malnourished than singletons and the odds of wasting, stunting, and underweight were 1.31, 1.83, and 1.73 times raised, consecutively. Nevertheless, multiple births regain their weight-for-age (WFA) and height-for-age (HFA) deficits by the end of the fourth year of age. Counseling pregnant mothers with multiple gestation to give birth at a health institution and providing close medical follow-up during and after the neonatal period can improve the survival of multiple births.

Objectives: This report presents 2013 data on U.S. births according to a wide variety of characteristics. Data are presented for maternal age, live-birth order, race and Hispanic origin, marital status, attendant at birth, method of delivery, period of gestation, birthweight, and plurality. Birth and fertility rates are presented by age, live-birth order, race and Hispanic origin, and marital status. Selected data by mother's state of residence and birth rates by age and race of father also are shown. Trends in fertility patterns and maternal and infant characteristics are described and interpreted., Methods: Descriptive tabulations of data reported on the birth certificates of the 3.93 million U.S. births that occurred in 2013 are presented., Results: A total of 3,932,181 births were registered in the United States in 2013, down less than 1% from 2012. The general fertility rate declined to 62.5 per 1,000 women aged 15-44. The teen birth rate fell 10%, to 26.5 per 1,000 women aged 15-19. Birth rates declined for women in their 20s and increased for most age groups of women aged 30 and over. The total fertility rate (estimated number of births over a woman's lifetime) declined 1% to 1,857.5 per 1,000 women. Measures of unmarried childbearing were down in 2013 from 2012. The cesarean delivery rate declined to 32.7%. The preterm birth rate declined for the seventh straight year to 11.39%, but the low birthweight rate was essentially unchanged at 8.02%. The twin birth rate rose 2% to 33.7 per 1,000 births; the triplet and higher-order multiple birth rate dropped 4% to 119.5 per 100,000 total births., (All material appearing in this report is in the public domain and may be reproduced or copied without permission; citation as to source, however, is appreciated.)

Objective: In March 2010, a new legislation about assisted reproductive technology (ART) activities, favoring single embryo transfer, was introduced in Turkey. Consequences of new regulations on neonatal outcome have not been evaluated in multicenter studies yet. In this study, our aim was to evaluate neonatal outcome of infants from medically assisted reproduction (MAR) pregnancies in the post-legislation era., Methods: A point prevalence study was conducted at 51 centers in Turkey on 1 April 2013. Data about fertility treatments and neonatal characteristics were evaluated for "live births" (Group 1) and "patients being cared in the NICU" (Group 2)., Results: Seventeen (4%) of 420 infants in group 1, and 89 (8.1%) of 1094 infants in group 2 were born after MAR pregnancies. The ratio of multiple births in MAR pregnancies was still very high as 47.1% for group 1, 69.1% for group 2 infants. MAR babies constituted 9.9% of infants in Level 3 NICUs and 7.6% infants in Level 2 NICUs. MAR was associated with increased risk of multiple births and prematurity., Conclusions: After the new legislation, multiple birth rates are still high in MAR pregnancies, resulting in unfavorable neonatal outcomes. Efforts to decrease multiple birth rates should be encouraged.