Search

Objectives (i) Estimate the proportion of non-registered prenatal ultrasound examinations; (ii) Examine associations between non-registered ultrasound examinations and adverse perinatal outcomes, by migrant-related factors, in women giving birth in Norway. Design A national population-based study. Setting and sample Individually linked data from the Medical Birth Registry of Norway and Statistics Norway, 1999-2016, comprising 999,760 singleton pregnancies to immigrants ( n = 196,220) and non-immigrants ( n = 803,540). Methods Crude and adjusted odds ratios (aOR) with 95% confidence intervals (CI) were estimated using logistic regression with robust standard error estimations, adjusted for year of childbirth, maternal age, parity, maternal smoking during pregnancy, educational level, and Norwegian health region at birth. Main outcome measures Prenatal ultrasound examinations; perinatal mortality; placental abruption; preeclampsia. Results Compared to non-immigrants, immigrant women had a higher proportion of non-registered ultrasound examinations (2.3% vs. 4.3% respectively). Compared to women with ultrasound examination, the aOR for perinatal mortality for women with non-registered ultrasound was 2.27 [95% CI 1.85, 2.79] for immigrants and 3.61 [3.21, 4.07] for non-immigrants. Non-registered ultrasound examination was also associated with placental abruption (aOR 1.32 [1.08, 1.63]) for non-immigrant women, but not for immigrant women. Non-registered ultrasound examination was not associated with preeclampsia in either immigrant or non-immigrant women. Conclusion Compared to non-immigrants, immigrant women have a higher proportion of non-registered data on prenatal ultrasound examinations. Both immigrants and non-immigrants with non-registered ultrasound examinations have an increased aOR of perinatal mortality, but no association was found for preeclampsia. Non-immigrant women had an increased aOR for placental abruption.

ObjectiveWe have previously found that allergy is a risk factor for early-onset pre-eclampsia. The aim of this study was to assess the association between pregestational maternal use of antihistamines and early-onset pre-eclampsia.DesignA population-based cohort study.Setting and participantsAll women giving birth in Norway 2004–2016, including 692 487 pregnancies. Data from the Medical Birth Registry of Norway were linked with data from the Norwegian Prescription Database. Prescriptions of antihistamines were divided into three groups: before pregnancy (InterventionsUse of antihistamines in relation to pregnancy in allergic women.Main outcome measuresDevelopment of early-onset pre-eclampsia.Results2997 (0.43%) and 5769 (0.83%) women had pre-eclampsia ConclusionsAntihistamine use before or during placentation was associated with reduced risk of developing early-onset pre-eclampsia in allergic women compared with women using antihistamines after placentation.

Introduction With increasing cesarean section rates, adverse pregnancy outcomes such as preterm delivery and small-for-gestational-age continue to be public health challenges. Besides having high co-occurrence and interrelation, it is suggested that these outcomes, along with preeclampsia, are associated with reduced subsequent fertility. On the other hand, the loss of a child during the perinatal period is associated with increased reproduction. Failure to consider this factor when estimating the effects of pregnancy outcomes on future reproduction may lead to erroneous conclusions. However, few studies have explored to what degree a perinatal loss contributes to having a next pregnancy in various adverse pregnancy outcomes. Material and methods This was a population-based study of mothers giving birth to their first singleton infant (≥22 gestational weeks) during 1967-2007 who were followed for the occurrence of a second birth in the Medical Birth Registry of Norway until 2014. Relative risks with 95% confidence intervals for having one lifetime pregnancy by preterm delivery, small-for-gestational-age, preeclampsia and cesarean section were obtained by generalized linear models for the binary family and adjusted for maternal age at first birth, education and year of first childbirth. Main outcome measure was having one lifetime pregnancy. Results Nearly 900 000 women gave birth to their first singleton infant in 1967-2007, of which 16% had only one lifetime pregnancy. These women were older at first delivery, had less education and there was a higher proportion of unmarried women than women with two or more births. In women with pregnancy complications where the infant survived the perinatal period, there were the following relative risks for one lifetime pregnancy: increased preterm delivery: 1.21 (1.19-1.22)], small-for-gestational-age: 1.13 (1.12-1.15), preeclampsia: 1.09 (1.07-1.11), cesarean section: 1.24 (1.23-1.25). The risk was significantly reduced if the child was lost (preterm delivery: 0.63 [0.59-0.68], small-for-gestational-age: 0.57 [0.51-0.63], preeclampsia: 0.69 [0.59-0.80], cesarean section: 0.67 [0.56-0.79]), compared with women with no perinatal loss and no adverse outcome. Conclusions The associations between adverse outcomes of pregnancy and the risk of having one lifetime pregnancy were strongly modified by child survival in the perinatal period.

BACKGROUND The rising prevalence of gestational diabetes mellitus (GDM) calls for the use of innovative methods to inform and empower these pregnant women. An information chatbot, Dina, was developed for women with GDM and is Norway’s first health chatbot, integrated into the national digital health platform. OBJECTIVE The aim of this study is to investigate what kind of information users seek in a health chatbot providing support on GDM. Furthermore, we sought to explore when and how the chatbot is used by time of day and the number of questions in each dialogue and to categorize the questions the chatbot was unable to answer (fallback). The overall goal is to explore quantitative user data in the chatbot’s log, thereby contributing to further development of the chatbot. METHODS An observational study was designed. We used quantitative anonymous data (dialogues) from the chatbot’s log and platform during an 8-week period in 2018 and a 12-week period in 2019 and 2020. Dialogues between the user and the chatbot were the unit of analysis. Questions from the users were categorized by theme. The time of day the dialogue occurred and the number of questions in each dialogue were registered, and questions resulting in a fallback message were identified. Results are presented using descriptive statistics. RESULTS We identified 610 dialogues with a total of 2838 questions during the 20 weeks of data collection. Questions regarding blood glucose, GDM, diet, and physical activity represented 58.81% (1669/2838) of all questions. In total, 58.0% (354/610) of dialogues occurred during daytime (8 AM to 3:59 PM), Monday through Friday. Most dialogues were short, containing 1-3 questions (340/610, 55.7%), and there was a decrease in dialogues containing 4-6 questions in the second period (P=.013). The chatbot was able to answer 88.51% (2512/2838) of all posed questions. The mean number of dialogues per week was 36 in the first period and 26.83 in the second period. CONCLUSIONS Frequently asked questions seem to mirror the cornerstones of GDM treatment and may indicate that the chatbot is used to quickly access information already provided for them by the health care service but providing a low-threshold way to access that information. Our results underline the need to actively promote and integrate the chatbot into antenatal care as well as the importance of continuous content improvement in order to provide relevant information.

Objective To estimate the incidence of placental abruption in immigrant women compared with non-immigrants by maternal country and region of birth, reason for immigration and length of residence. Design Nationwide population-based study. Setting Data from the Medical Birth Registry of Norway and Statistics Norway (1990-2016). Sample The study sample included 1,558,174 pregnancies, in which immigrant women accounted for 245,887 pregnancies and 1,312,287 pregnancies were to non-immigrants. Methods Crude and adjusted odds ratios with 95% confidence intervals (CI) for placental abruption in immigrant women compared to non-immigrants were estimated by logistic regression with robust standard error estimations (accounting for within-mother clustering). Adjustment variables included year of birth, maternal age, parity, multiple pregnancies, chronic hypertension and level of education. Main outcome measures Placental abruption Results The incidence of placental abruption decreased during the study period for both immigrants (from 0.68% to 0.44%) and non-immigrants (from 0.80% to 0.34%). Immigrant women from the sub-Saharan African region had an adjusted odds ratio of 1.35 (95% CI: 1.15-1.58) compared to non-immigrants for placental abruption, whereas immigrant women from Ethiopia had an adjusted odds ratio of 2.39 (95% CI 1.67-3.41). We found a small variation in placental abruption incidence by other countries or regions of birth, length of residence and reason for immigration. Conclusion Immigrant women from sub-Saharan Africa, especially Ethiopia, have increased odds for placental abruption when giving birth in Norway. Reason for immigration and length of residence had little impact on the incidence of placental abruption.

Objective: To estimate recurrence risk of gestational diabetes mellitus (GDM) by interpregnancy weight change. Design: Population-based cohort study. Setting and population: Data from the Swedish (1992–2010) and the Norwegian (2006–2014) Medical Birth Registries on 2763 women with GDM in first pregnancy, registered with their first two singleton births and available information on height and weight. Methods: Interpregnancy weight change (BMI in second pregnancy minus BMI in first pregnancy) was categorised in six groups by BMI units. Relative risks (RRs) of GDM recurrence were obtained by general linear models for the binary family and adjusted for confounders. Analyses were stratified by BMI in first pregnancy (2 units (RR 0.72, 95% CI 0.59–0.89) and increased if BMI increased by ≥4 units (RR 1.26, 95% CI 1.05–1.51) compared wth women with stable BMI (−1 to 1 units). In normal weight women (BMI

Objective To examine the association between availability of obstetric institutions and risk of eclampsia, HELLP-syndrome, or delivery before 35 gestational weeks in preeclamptic pregnancies. Study design National population-based retrospective cohort study of deliveries in Norway, 1999–2009 (n = 636738) using data from The Medical Birth Registry of Norway and Statistics Norway. Main exposures were institution availability, measured by travel time to the nearest obstetric institution, and place of delivery. We computed relative risks (RR) with 95% confidence intervals (CI) using travel time ≤1 h as reference. We stratified analyses by parity and preeclampsia, and adjusted for socio-demographic and medical risk factors. Successive deliveries were linked using the national identification number. Results We identified 1387 eclampsia/HELLP cases (0.2%) and 3004 (0.5%) deliveries before 35 weeks in preeclamptic pregnancies. Nulliparous women living >1 h from any obstetric institution had 50% increased risk of eclampsia/HELLP (0.50 versus 0.35%, adjusted RR 1.5; 95 %CI 1.1–1.9). Parous women living >1 h from emergency institutions had a doubled risk of eclampsia (0.6‰ versus 0.3‰, adjusted RR 2.0; 1.2–3.3). Women without preeclampsia in the present pregnancy or history of preeclampsia constituted all eclampsia/HELLP cases in midwife-led institutions, 39–50% of cases in emergency institutions, and 78% of cases (135/173) in subsequent deliveries. Women with risk factors delivered in the emergency institutions, indicating well-implemented selective referral. Conclusion The study shows the importance of available obstetric institutions. Policymakers and clinicians should consider the distribution of potential benefits and burdens when planning and evaluating the obstetric health service structure.

Introduction Some studies have suggested that women may avoid further pregnancies after experiencing a pregnancy affected by a hypertensive disorder. Large population-based studies are needed to better understand the outcomes of later pregnancies among women who have a history of hypertensive disorders of pregnancy. The aims of the study were to assess outcomes of the second pregnancy and second delivery rate among women experiencing Hemolysis, elevated liver enzymes and low platelet count (HELLP) syndrome in their first pregnancy. Material and methods This population-based registry study included all women with a first delivery registered in the Medical Birth Registry of Norway from 1999 to 2014 (n = 418 897). Logistic regression was used to estimate odds ratios (ORs) with 95% confidence intervals (CIs) for adverse outcomes of the second delivery and the probability of no second delivery among women with HELLP syndrome in first pregnancy compared with women without HELLP syndrome. We also compared outcomes in the first and second pregnancies among women with HELLP syndrome in first. Results HELLP syndrome occurred in 0.24% of first pregnancies (n = 1006). Among women with HELLP syndrome in their first pregnancy, adverse outcomes were substantially less frequent in the second pregnancy: preterm deliveries declined from 56.0% to 14.2%, and small for gestational age from 6.6% to 2.8%. More than 75% had no hypertensive disorder in their second pregnancy. Still, compared with women without a history of HELLP syndrome, ORs for adverse outcomes in second pregnancies were increased: preterm birth (OR 3.7, 95% CI 2.8-4.8), small for gestational age (OR 2.7, 95% CI 1.6-4.8), perinatal death (OR 3.1, 95% CI 1.4-7.0), placental abruption (OR 4.2, 95% CI 1.8-9.4) and hypertensive complication (OR 8.3, 95% CI 6.7-10.3). HELLP syndrome did not influence the probability of a second delivery. Conclusions Among women with HELLP syndrome in their first pregnancy, the occurrence of adverse pregnancy outcomes was substantially reduced in the second pregnancy. However, compared with unaffected women, they were still at greater risk of pregnancy complications.

Objectives Childbearing at extremely advanced maternal age is a globally increasing trend, but only a few studies have described the outcomes of these pregnancies. The aim of this study was to describe the occurrence of childbearing at age 50 and up in the Nordic countries, as well as to examine the frequency of adverse obstetric and neonatal outcomes. Study design A descriptive population-based study was designed. Data from 1991 to 2013 were collected from the Medical Birth Registries in Denmark, Finland, Norway and Sweden. We investigated the occurrence of antepartum, delivery and neonatal outcomes. Results A total of 170 deliveries, in 141 singleton and 29 multiple pregnancies, were identified in mothers aged 50 and up. The highest frequency during this period was 6 per 100,000 deliveries. The prevalence for selected adverse outcomes in singleton pregnancies were: intrauterine fetal death (IUFD) 6%, preeclampsia 4%, preterm delivery 14%, gestational diabetes 8% and cesarean delivery 50%. In multiple pregnancies, the respective prevalence were: IUFD 2%, preeclampsia 22%, preterm delivery 57%, gestational diabetes 10% and cesarean delivery 79%. Pregnancy after assisted reproductive technologies was frequent (29% of singleton and 50% of multiple pregnancies). Conclusions This study found high frequency of obstetric and neonatal complications at extremely advanced maternal age. Despite a high prevalence of stillbirth in singleton pregnancies in the studied Nordic countries, other complications were less frequent than those previously reported in different populations. Adequate preconception consultation concerning maternal and neonatal hazards is highly recommended in this group of women.

Objectives To estimate the burden of miscarriage in the Norwegian population and to evaluate the associations with maternal age and pregnancy history. Design Prospective register based study. Setting Medical Birth Register of Norway, the Norwegian Patient Register, and the induced abortion register. Participants All Norwegian women that were pregnant between 2009-13. Main outcome measure Risk of miscarriage according to the woman’s age and pregnancy history estimated by logistic regression. Results There were 421 201 pregnancies during the study period. The risk of miscarriage was lowest in women aged 25-29 (10%), and rose rapidly after age 30, reaching 53% in women aged 45 and over. There was a strong recurrence risk of miscarriage, with age adjusted odds ratios of 1.54 (95% confidence interval 1.48 to 1.60) after one miscarriage, 2.21 (2.03 to 2.41) after two, and 3.97 (3.29 to 4.78) after three consecutive miscarriages. The risk of miscarriage was modestly increased if the previous birth ended in a preterm delivery (adjusted odds ratio 1.22, 95% confidence interval 1.12 to 1.29), stillbirth (1.30, 1.11 to 1.53), caesarean section (1.16, 1.12 to 1.21), or if the woman had gestational diabetes in the previous pregnancy (1.19, 1.05 to 1.36). The risk of miscarriage was slightly higher in women who themselves had been small for gestational age (1.08, 1.04 to 1.13). Conclusions The risk of miscarriage varies greatly with maternal age, shows a strong pattern of recurrence, and is also increased after some adverse pregnancy outcomes. Miscarriage and other pregnancy complications might share underlying causes, which could be biological conditions or unmeasured common risk factors.

Due to a low level of understanding of mechanisms involved in spontaneous preterm delivery there is a lack of reliable biomarkers. Existing biomarkers have a low positive predictive value but a high negative predictive value. Use of tests with high negative predictive value will reduce unnecessary interventions and hospitalization of women with threatening preterm delivery. When given to the right pregnant women, antenatal corticosteroid treatment are still the most important obstetrical intervention and reduces both neonatal mortality and short- and long-term morbidity.Several ongoing national Swedish multicenter studies may increase the understanding of the roles of cervical length, preeclampsia screening and magnesium sulfate dosage in the context of preterm delivery in a Nordic setting. Major development has been achieved in prediction and prevention of preterm preeclampsia at the cost of a 10% screen positive rate.

Background Pregnant women who request a cesarean section in the absence of obstetric indication have become a highly debated issue in academic as well as popular literature. In order to find adequate, targeted treatment and preventive strategies, we need a better understanding of this phenomenon. The aim of this study is to provide a qualitative exploration of maternal requests for a planned cesarean section in Norway, in the absence of obstetric indications. Methods A descriptive qualitative study was conducted consisting of 17 semi-structured, in-depth interviews with women requesting cesarean section and six focus group discussions with 20 caregivers (nine midwives, 11 obstetricians) working at a university hospital in Norway. Data were analyzed with Systematic Text Condensation, a method for thematic cross-case analysis. Results Fear of birth emerged most commonly as a result of a previous traumatic birth experience that prompted a preference for a planned cesarean to avoid a repetition of the trauma. For some women in our study, postnatal care and the puerperal period were their crucial past experiences, and giving birth by planned cesarean was seen as a way to ensure mental rather than physical capability to care for the expected child after birth. Others were under the impression of being at high risk for an emergency C-section, and requesting a planned one was based on their perceived risk. Such perceptions included having a narrow pelvis, hereditary factors or previous birth outcomes. Some primiparas requested a planned cesarean based on a deep-seated fear since their early teens, accompanied by alienation towards the idea of giving birth. Some obstetricians participating in our study also experienced requests that lacked what they regarded as any well-grounded reason or significant fear. Conclusions Behind a maternal request for a planned cesarean section are various rationales and life experiences needing carefully targeted attention and health care. Previous births are an important driver; thus, maternally requested cesareans should be regarded partly as an iatrogenic problem. Electronic supplementary material The online version of this article (10.1186/s12884-019-2250-6) contains supplementary material, which is available to authorized users.

Interview guide for in-depth interviews with women. Questions and probes used in interviews with women. (DOCX 15 kb)

Interview guide for focus group discussions with caregivers. Questions and probes used in focus group discussions with caregivers. (DOCX 14 kb)

Objective Low parity women are at increased risk of cardiovascular mortality. Unfavourable lipid profiles have been found in one-child mothers years before they conceive. However, it remains unclear whether unfavourable lipid profiles are evident in these women also after their first birth. The aim was to estimate post-pregnancy lipid levels in one-child mothers compared to mothers with two or more children and to assess these lipid’s associations with number of children. Methods We used data on 32 618 parous women (4 490 one-child mothers and 28 128 women with ≥2 children) examined after first childbirth as part of Cohort of Norway (1994–2003) with linked data on reproduction and number of children from the Medical Birth Registry of Norway (1967–2008). Odds ratios (ORs) with 95% confidence intervals (CIs) for one lifetime pregnancy (vs. ≥2 pregnancies) by lipid quintiles were obtained by logistic regression and adjusted for age at examination, year of first birth, body mass index, oral contraceptive use, smoking and educational level. Results Compared to women with the lowest quintiles, ORs for one lifetime pregnancy for the highest quintiles of LDL and total cholesterol were 1.30 (95%CI: 1.14–1.45) and 1.43 (95%CI: 1.27–1.61), respectively. Sensitivity analysis (women

Objective This study aimed to explore women's access to patient-centered counseling for concerns initiating cesarean requests in absence of obstetric indications in pregnancy, and to identify tensions, barriers and facilitators affecting such care. Design, setting and informants This qualitative study (June 2016 to August 2017) obtained data through semi-structured in-depth interviews with 17 women requesting planned C-section during birth counseling at a university hospital in Norway and focus group discussions with 20 caregivers (9 midwives and 11 obstetricians) employed at the same hospital. Analysis was carried out by systematic text condensation, a method for thematic analysis in medical research, presented within the frames of Levesque and colleagues’ conceptual framework of access to patient-centered care. Findings The analysis revealed that there were considerable tensions in care seeking and provision of counseling for maternal requests for C-section. There was a prominent culture of vaginal delivery among caregivers and women. The appropriateness of CS on maternal request was debated and caregivers revealed diverging attitudes and practices when agreement with women was not reached. Women's views on their entitlement to choose were divided, but the majority of women did not support complete maternal choice. Midwife-led counseling were highly appreciated among woman as well as obstetricians. Implications for practice Tensions and barriers in care seeking and provision of counseling for women requesting C-section for non-obstetric reasons, call for standardized counseling in order for equal and adequate care to be provided across health care institutions and providers. Dialogue-based decision-making and midwife-led care may improve satisfaction of care, enhance spontaneous vaginal deliveries and avoid future conflicts.

Background Gestational age estimation by last menstrual period (LMP) vs. ultrasound (or best obstetric estimate in the US) may result in discrepant classification of preterm vs. term birth. We investigated whether such discrepancies are associated with adverse infant outcomes. Methods We studied singleton livebirths in the Medical Birth Registries of Norway, Sweden and Finland and US live birth certificates from 1999 to the most recent year available. Risk ratios (RR) with 95% confidence intervals (CI) by discordant and concordant gestational age estimation for infant, neonatal and post-neonatal mortality, Apgar score

Background Prenatal exposure to perfluoroalkyl substances (PFAS) has been associated with lower birth weight in epidemiologic studies. This association could be attributable to glomerular filtration rate (GFR), which is related to PFAS concentration and birth weight. Objectives We used a physiologically based pharmacokinetic (PBPK) model of pregnancy to assess how much of the PFAS–birth weight association observed in epidemiologic studies might be attributable to GFR. Methods We modified a PBPK model to reflect the association of GFR with birth weight (estimated from three studies of GFR and birth weight) and used it to simulate PFAS concentrations in maternal and cord plasma. The model was run 250,000 times, with variation in parameters, to simulate a population. Simulated data were analyzed to evaluate the association between PFAS levels and birth weight due to GFR. We compared simulated estimates with those from a meta-analysis of epidemiologic data. Results The reduction in birth weight for each 1-ng/mL increase in simulated cord plasma for perfluorooctane sulfonate (PFOS) was 2.72 g (95% CI: –3.40, –2.04), and for perfluorooctanoic acid (PFOA) was 7.13 g (95% CI: –8.46, –5.80); results based on maternal plasma at term were similar. Results were sensitive to variations in PFAS level distributions and the strength of the GFR–birth weight association. In comparison, our meta-analysis of epidemiologic studies suggested that each 1-ng/mL increase in prenatal PFOS and PFOA levels was associated with 5.00 g (95% CI: –21.66, –7.78) and 14.72 g (95% CI: –8.92, –1.09) reductions in birth weight, respectively. Conclusion Results of our simulations suggest that a substantial proportion of the association between prenatal PFAS and birth weight may be attributable to confounding by GFR and that confounding by GFR may be more important in studies with sample collection later in pregnancy. Citation Verner MA, Loccisano AE, Morken NH, Yoon M, Wu H, McDougall R, Maisonet M, Marcus M, Kishi R, Miyashita C, Chen MH, Hsieh WS, Andersen ME, Clewell HJ III, Longnecker MP. 2015. Associations of perfluoroalkyl substances (PFAS) with lower birth weight: an evaluation of potential confounding by glomerular filtration rate using a physiologically based pharmacokinetic model (PBPK). Environ Health Perspect 123:1317–1324; http://dx.doi.org/10.1289/ehp.1408837

Importance Clinicians have been urged to delay the use of obstetric interventions (eg, labor induction, cesarean delivery) until 39 weeks or later in the absence of maternal or fetal indications for intervention. Objective To describe recent trends in late preterm and early term birth rates in 6 high-income countries and assess association with use of clinician-initiated obstetric interventions. Design Retrospective analysis of singleton live births from 2006 to the latest available year (ranging from 2010 to 2015) in Canada, Denmark, Finland, Norway, Sweden, and the United States. Exposures Use of clinician-initiated obstetric intervention (either labor induction or prelabor cesarean delivery) during delivery. Main Outcomes and Measures Annual country-specific late preterm (34-36 weeks) and early term (37-38 weeks) birth rates. Results The study population included 2 415 432 Canadian births in 2006-2014 (4.8% late preterm; 25.3% early term); 305 947 Danish births in 2006-2010 (3.6% late preterm; 18.8% early term); 571 937 Finnish births in 2006-2015 (3.3% late preterm; 16.8% early term); 468 954 Norwegian births in 2006-2013 (3.8% late preterm; 17.2% early term); 737 754 Swedish births in 2006-2012 (3.6% late preterm; 18.7% early term); and 25 788 558 US births in 2006-2014 (6.0% late preterm; 26.9% early term). Late preterm birth rates decreased in Norway (3.9% to 3.5%) and the United States (6.8% to 5.7%). Early term birth rates decreased in Norway (17.6% to 16.8%), Sweden (19.4% to 18.5%), and the United States (30.2% to 24.4%). In the United States, early term birth rates decreased from 33.0% in 2006 to 21.1% in 2014 among births with clinician-initiated obstetric intervention, and from 29.7% in 2006 to 27.1% in 2014 among births without clinician-initiated obstetric intervention. Rates of clinician-initiated obstetric intervention increased among late preterm births in Canada (28.0% to 37.9%), Denmark (22.2% to 25.0%), and Finland (25.1% to 38.5%), and among early term births in Denmark (38.4% to 43.8%) and Finland (29.8% to 40.1%). Conclusions and Relevance Between 2006 and 2014, late preterm and early term birth rates decreased in the United States, and an association was observed between early term birth rates and decreasing clinician-initiated obstetric interventions. Late preterm births also decreased in Norway, and early term births decreased in Norway and Sweden. Clinician-initiated obstetric interventions increased in some countries but no association was found with rates of late preterm or early term birth.

Breastfeeding (BF) has been reported to improve long-term maternal metabolic health in observational studies, but not in the randomised controlled PROBIT study. Research also suggests that maternal pre-pregnant metabolic health may affect BF. We aimed to disentangle effects of BF on long-term maternal metabolic health from effects of pre-pregnant metabolic health on BF duration and long-term metabolic health.Longitudinal population-based cohort study.Nord-Trøndelag county, Norway.Women with a first live-born baby (1987-2008) participating in the Nord-Trøndelag Health Study (HUNT).Odds ratios (ORs) for short BF duration (3 months) by pre-pregnant body mass index (BMI), waist circumference (WCF), blood pressures (BPs), and heart rate (HR) were adjusted for age and smoking using logistic regression. Mixed linear models were used to estimate effects of BF duration (3, 3-6,6 months) on mean values of metabolic health parameters from baseline to follow-up.Mean change in BMI, WCF, BPs, HR, serum-glucose, and serum-lipids from baseline to follow-up by BF duration categories.We analysed 1403 women with a median follow-up of 12 years (interquartile range 11-22). Pre-pregnant WCF and HR correlated inversely with BF duration. Pre-pregnant BMI had a u-shaped correlation-pattern with BF duration. We observed similar between-group differences in metabolic health parameters at baseline and at follow-up, which implies that mean change in metabolic health parameters was similar across BF groups. Those women who started out with the best health had the longest BF duration and ended up with the best health, and those women who started out with the poorest health had shortest BF duration and ended up with the poorest health.Our results do not support a causal relationship between long BF duration and improved metabolic health. It is more likely that pre-pregnant metabolic health affects both BF duration and long-term metabolic health. Reverse causality can explain previously observed improved long-term metabolic health after BF.Breastfeeding seems not to affect long-term maternal metabolic health, but good pre-pregnant metabolic health does.

Objective To study prepregnancy serum lipid levels and the association with the number of children. Design Prospective, population-based cohort. Setting Linked data from the Cohort of Norway and the Medical Birth Registry of Norway. Participants 2645 women giving birth to their first child during 1994–2003 (488 one-child mothers and 2157 women with ≥2 births) and 1677 nulliparous women. Main outcome measures ORs for no and one lifetime pregnancy (relative to ≥2 pregnancies) obtained by multinomial logistic regression, adjusted for age at examination, education, body mass index (BMI), smoking, time since last meal and oral contraceptive use. Results Assessed in quintiles, higher prepregnant triglyceride (TG) and TG to high-density lipoprotein (TG:HDL-c) ratio levels were associated with increased risk of one lifetime pregnancy compared with having ≥2 children. Compared with the highest quintile, women in the lowest quintile of HDL cholesterol levels had an increased risk of one lifetime pregnancy (OR 1.7, 95% CI 1.2 to 2.4), as were women with the highest low-density lipoprotein (LDL) cholesterol, TG and TG:HDL-c ratio quintiles (compared with the lowest) (OR 1.2, 95% CI 0.8 to 1.7; OR 2.2, 95% CI 1.5 to 3.2; and OR 2.2, 95% CI 1.5 to 3.2, respectively). Similar effects were found in women with BMI≥25 and the highest LDL and total cholesterol levels in risk of lifetime nulliparity. Conclusion Women with unfavourable prepregnant lipid profile had higher risk of having no or only one child. These findings substantiate an association between prepregnant serum lipid levels and number of children. Previously observed associations between low parity and increased cardiovascular mortality may in part be due to pre-existing cardiovascular disease lipid risk factors.

OBJECTIVES: To explore international differences in the classification of births at extremely low gestation and the subsequent impact on the calculation of survival rates. METHODS: We used national data on births at 22 to 25 weeks’ gestation from the United States (2014; n = 11 144), Canada (2009–2014; n = 5668), the United Kingdom (2014–2015; n = 2992), Norway (2010–2014; n = 409), Finland (2010–2015; n = 348), Sweden (2011–2014; n = 489), and Japan (2014–2015; n = 2288) to compare neonatal survival rates using different denominators: all births, births alive at the onset of labor, live births, live births surviving to 1 hour, and live births surviving to 24 hours. RESULTS: For births at 22 weeks’ gestation, neonatal survival rates for which we used live births as the denominator varied from 3.7% to 56.7% among the 7 countries. This variation decreased when the denominator was changed to include stillbirths (ie, all births [1.8%–22.3%] and fetuses alive at the onset of labor [3.7%–38.2%]) or exclude early deaths and limited to births surviving at least 12 hours (50.0%–77.8%). Similar trends were seen for infants born at 23 weeks’ gestation. Variation diminished considerably at 24 and 25 weeks’ gestation. CONCLUSIONS: International variation in neonatal survival rates at 22 to 23 weeks’ gestation diminished considerably when including stillbirths in the denominator, revealing the variation arises in part from differences in the proportion of births reported as live births, which itself is closely connected to the provision of active care.

Objectives To estimate the risk of hypertensive pregnancy complications in women with epilepsy, with and without antiepileptic drugs, and assess the risk associated with the four most common antiepileptic drugs. Design A population-based cohort study using linked data from the Medical Birth Registry of Norway and the Norwegian Prescription Database. Women with epilepsy with and without antiepileptic drugs were compared with women without epilepsy. Setting Norway, 2004–2012. Participants All first pregnancies of women with epilepsy and women without epilepsy were included. Primary and secondary outcome measures Main outcome measures were hypertensive pregnancy complications: a compound variable of any hypertensive disorder, gestational hypertension, mild pre-eclampsia, severe pre-eclampsia, early onset pre-eclampsia, eclampsia and HELLP syndrome (haemolysis, elevated liver enzymes, low platelets). Results In total, 1778 pregnancies in women with epilepsy and 221 662 in women without epilepsy were analysed. 682 of the women with epilepsy used antiepileptic drugs, the most common in monotherapy being: lamotrigine (n=280), carbamazepine (n=94), levetiracetam (n=71) and valproate (n=51). There was an increased risk of any hypertensive disorder in women with epilepsy (adjusted OR (aOR) 1.2, 95% CI 1.0 to 1.5) and in the subcategory using valproat (aOR 2.9, 95% CI 1.3 to 6.4). The most frequent hypertensive complication was mild pre-eclampsia and the risk was increased in women with epilepsy (aOR 1.4, 95% CI 1.1 to 1.8) and women with epilepsy with valproat (aOR 3.3, 95% CI 1.2 to 9.4). Conclusions Women with epilepsy have an increased risk of mild pre-eclampsia, but not for the severe types of hypertensive pregnancy complications. Lamotrigine and levetiracetam do not predispose for mild pre-eclampsia, whereas valproate was associated with an increased risk of mild pre-eclampsia.

Immunological mechanisms underlying the development of preeclampsia are well known, but no association to allergy has yet been demonstrated. The aim of this study was to assess the correlation between maternal pre-gestational allergy, and early-onset and late-onset preeclampsia, respectively. It was a retrospective cohort study including all women giving birth in the Norwegian cities of Stavanger (1996-2014) and Bergen (2009-2014). Pre-gestational asthma, allergy, other known risk factors for preeclampsia, maternal age and parity were obtained from the electronic medical record system. The main outcome variables were early-onset and late-onset preeclampsia (before and after 34 completed weeks of gestation, respectively). We used multinomial logistic regression to estimate odds ratios (OR) with 95% confidence intervals (95% CI) for early and late-onset preeclampsia in women with pre-gestational allergy when compared to women without allergy, adjusting for covariates. Predicted probabilities for the outcomes were also calculated. Of the 110 064 included pregnancies, 2 799 developed late-onset preeclampsia (2.5%) and 348 developed early-onset preeclampsia (0.3%). Pre-gestational allergy increased the risk of early-onset preeclampsia (OR 1.7, 95% CI 1.3-2.4), and reduced the risk of late-onset preeclampsia (OR 0.8, 95% CI 0.7-0.9). These findings add valuable information on preeclampsia as an immunological complication of pregnancy and corroborate the understanding of early- and late-onset preeclampsia as two different entities.

Introduction HELLP syndrome (hemolysis, elevated liver enzymes, and low platelet count) may have specific risk factors and risk factors varying from first to second pregnancy. The aims of the study were to estimate the risk of HELLP syndrome by potential risk factors in first and second pregnancy, respectively. Material and methods A population-based cohort study including all women in Norway having their first baby (≥22 gestational weeks) during 1999 to 2014, registered in the Medical Birth Registry (n = 418 897). A subset of women with at least two births (n = 249 070) was used for estimates in second pregnancy. Relative risks with 95% CIs for HELLP syndrome were estimated using logistic regression and adjusted for maternal age and year of childbirth. Results Body mass index ≥30 kg/m2 and diabetes were associated with HELLP syndrome in first, but not in second pregnancy. Chronic hypertension and multiple pregnancy were associated with HELLP syndrome both in first and second pregnancy. In second pregnancy the strongest risk factors were a history of HELLP syndrome or preterm preeclampsia in the first. The risk was inversely correlated with gestational age at first delivery. The overall relative risk for recurrence of HELLP syndrome was 54.4 (95% CI 34.3-86.2) and 129.5 (95% CI 45.7-367.2) after HELLP syndrome before 29 weeks of gestation in first pregnancy. Conclusions Important risk factors for HELLP syndrome differ from first to second pregnancy. HELLP syndrome in second pregnancy is rare, but the relative risk is very high in women with HELLP syndrome or preterm preeclampsia in their first pregnancy.

Objective To identify high-risk fetuses at the first routinely performed ultrasound examination by making use of information from the mother's previous pregnancy. Design A population-based cohort study. Setting Norway, 1999–2009. Population All singleton first live births and their second-born siblings registered in the Medical Birth Registry of Norway (166 786 eligible sibling pairs). Methods Odds ratios were calculated by logistic regression. Main outcome measures Very small for gestational age (vSGA; birthweight ≤−1.96 standard deviations) and perinatal death (stillbirth at ≥22 weeks of gestation or death within 28 days of life). Results Small fetal size at ultrasound (i.e. a fetus smaller than expected by last menstrual period, LMP) is only weakly predictive of vSGA or perinatal death; however, if the firstborn sibling was vSGA at birth, ultrasound measures in the next pregnancy become strongly informative of risk. The smaller the fetal size on ultrasound, the higher its risk of vSGA (3–18%; Ptrend

Background Smoking during pregnancy is linked to having a small for gestational age (SGA) baby. We estimated SGA risk among women who smoked persistently, quit smoking or started smoking during their first two pregnancies. Methods Data from the population-based Medical Birth Registry of Norway was used to evaluate self-reported smoking at the beginning and end of two successive pregnancies among 118 355 Nordic women giving birth 1999–2014. Relative risks (RR) with 95% confidence intervals (CI) of SGA in the second pregnancy were estimated using adjusted generalised linear models with non-smokers during both pregnancies serving as referent category. Results Daily smokers throughout both pregnancies had almost threefold increased SGA risk in the second pregnancy (RR 2.9, 95% CI 2.7, 3.1). Daily smokers in the first pregnancy, who abstained in the second, had a 1.3-fold increased risk (95% CI 1.1, 1.5). Intermediate risks were found among persistent daily smokers who quit by the end of the second pregnancy (RR 2.0, 95% CI 1.6, 2.4) and non-smokers in first pregnancy who smoked daily throughout their second (RR 1.8, 95% CI 1.4, 2.3). Persistently smoking women without SGA in first pregnancy, had a 2.7-fold increased risk of SGA in second pregnancy (95% CI 2.5, 3.0). Conclusions Smoking throughout two successive pregnancies was associated with the greatest increased SGA risk compared with non-smokers, while cessation before or during the second pregnancy reduced this risk. Women who smoked in the first pregnancy without experiencing SGA are not protected against SGA in second pregnancy if they continue smoking.

BackgroundPrediction of a woman's risk of a spontaneous preterm delivery (PTD) is a core challenge and an unresolved problem in today's obstetric practice. The objective of this study was to develop prediction models for spontaneous PTD (

Background Preterm delivery (PTD) is the leading cause of neonatal morbidity and mortality. Epidemiologic studies indicate recurrence of PTD is maternally inherited creating a strong possibility that mitochondrial variants contribute to its etiology. This study examines the association between mitochondrial genotypes with PTD and related outcomes. Methods This study combined, through meta-analysis, two case-control, genome-wide association studies (GWAS); one from the Danish National Birth Cohort (DNBC) Study and one from the Norwegian Mother and Child Cohort Study (MoBa) conducted by the Norwegian Institute of Public Health. The outcomes of PTD (≤36 weeks), very PTD (≤32 weeks) and preterm prelabor rupture of membranes (PPROM) were examined. 135 individual SNP associations were tested using the combined genome from mothers and neonates (case vs. control) in each population and then pooled via meta-analysis. Results After meta-analysis there were four SNPs for the outcome of PTD below p≤0.10, and two below p≤0.05. For the additional outcomes of very PTD and PPROM there were three and four SNPs respectively below p≤0.10. Conclusion Given the number of tests no single SNP reached study wide significance (p=0.0006). Our study does not support the hypothesis that mitochondrial genetics contributes to the maternal transmission of PTD and related outcomes.

Pre-eclampsia is a leading complication of pregnancy, associated with maternal and neonatal morbidity. The present study describes the epidemiology of pre-eclampsia in Norway, with data from the Medical Birth Registry of Norway, covering 40 years. We aimed at describing time trends in prevalence, selected risk factors and perinatal mortality. We also analysed time trends in recurrence risk of total pre-eclampsia and pre-eclampsia with preterm delivery. A total of 2,416,501 women giving birth during 1967-2008 were included. Prevalence of pre-eclampsia increased from 1967 to 1999 and decreased thereafter, with an overall prevalence of 3%. Rates increased more over time among younger than older women, resulting in a significantly lower excess risk of pre-eclampsia associated with high maternal age in later years. For example, relative risk (RR) of pre-eclampsia among primiparae aged ≥35 relative to

OBJECTIVE To assess the effects of socioeconomic factors on the association between parity and long-term maternal mortality. METHODS This was a population-based cohort study of mothers with births registered in the Medical Birth Registry of Norway during the period 1967-2009. We estimated age-specific (40-69 years) cardiovascular and noncardiovascular mortality ratios by number of births using Cox proportional hazard models. To assess effect modification by mothers' attained education, we stratified on low (less than 11 years) and high (11 years or greater) educational level. We further evaluated fathers' mortality by number of births using the same analytical approach. RESULTS Mothers with low education had higher mortality (cardiovascular: hazard ratio 2.62, 95% confidence interval [CI] 2.34-2.93, noncardiovascular: hazard ratio 1.67, 95% CI 1.62-1.73). Among mothers with low education, cardiovascular mortality increased linearly with each additional birth above one (P trend=.02). In contrast, among mothers with high education, cardiovascular mortality declined with added births (P trend=.045). For noncardiovascular mortality there was no association among mothers with low education, whereas mortality declined with increasing number of births among mothers with high education (P trend

Please cite this paper as: Morken N-H, Melve K, Skjaerven R. Recurrence of prolonged and post-term gestational age across generations: maternal and paternal contribution. BJOG 2011;118:1630–1635. Objective To estimate intergenerational recurrence risk of prolonged and post-term gestational age. Design Population-based cohort study. Setting Norway, 1967–2006. Population Intergenerational data from the Medical Birth Registry of Norway of singleton mothers and fathers giving birth to singleton children: 478 627 mother–child units and 353 164 father–child units. A combined mother–father–child file including 295 455 trios was also used. Methods Relative risks were obtained from contingency tables and relative risk modelling. Main outcome measures Gestational age ≥41 weeks (≥287 days), ≥42 weeks (≥294 days) and ≥43 weeks (≥301 days) of gestation in the second generation. Results A post-term mother (≥42 weeks) had a 49% increased risk of giving birth to a child at ≥42 weeks (relative risk [RR] 1.49, 95% CI 1.47–1.51) and a post-term father had a 23% increased risk of fathering a child at ≥42 weeks (RR 1.23, 95%CI 1.20–1.25). The RRs for delivery at ≥41 weeks were 1.29 (1.28–1.30) and 1.14 (1.13–1.16) for mother and father, respectively, and for ≥43 weeks 1.55 (1.50–1.59) and 1.22 (1.17–1.27). The RR of a pregnancy at ≥42 weeks in the second generation was 1.76 (1.68–1.84) if both mother and father were born post-term. Adjustment for maternal age in both generations, fetal sex in the second generation, parity, and maternal and paternal birthweight did not influence the risk estimates. Conclusions There is a familial factor related to recurrence of prolonged pregnancy across generations and both mother and father seem to contribute.

Objectives To assess the risk of spontaneous and iatrogenic preterm delivery in singleton pregnancies when comparing in vitro fertilization (IVF) pregnancies with intracytoplasmic sperm injection (ICSI) pregnancies. Study design A national population-based cohort study using Norwegian Medical Birth Register data during 1999 through 2006 was designed. The cohort included 5824 singleton pregnancies after IVF and ICSI treatment. Multinomial logistic regression analyses were used to calculate risk estimates. Results There were no differences in maternal complicating factors such as pre-eclampsia, hypertension and diabetes between the IVF and ICSI pregnancies. However, IVF pregnancies had a 60% increased risk of moderately (32 + 0 days –36 + 6 days gestational weeks) iatrogenic preterm delivery (OR: 1.6, 95%CI: 1.1–2.2) and a 40% increased risk of iatrogenic preterm delivery Conclusion IVF pregnancies were at increased risk of moderately iatrogenic preterm delivery when compared to ICSI pregnancies.

Immunosuppressive drugs may influence spermatogenesis, but little is known about outcome of pregnancies fathered by transplanted males. We estimated risk of adverse outcomes in pregnancies (with data after the first trimester) fathered by males that had undergone organ transplantation and were treated with immunosuppression. A population-based study, linking data from the Norwegian transplant registry and the Medical Birth Registry of Norway during 1967-2009 was designed. All Norwegian men undergoing solid organ transplantation were included. Odds ratios for major malformations, preeclampsia, preterm delivery (

Objective: This study was undertaken to assess whether deviations from normal fetal growth are associated with spontaneous preterm delivery. Study design: A population-based study was performed, using Swedish Medical Birth Register data from 1991 through 2001. The total population comprised 1,007,648 singleton births. Intrauterine-derived growth standards were used to identify individual standard deviation (SD) from expected birth weight. Spontaneous preterm infants were compared with infants born after spontaneous labor at term. Results were obtained by using multiple logistic regression analysis. Results: Associations between smaller than population mean and spontaneous preterm birth were evident for all gestational age groups. The largest risk was found at 28 to 31 gestational weeks and birth weight less than -3 SD (OR: 13.3; 95% CI: 10.3-17.2). Spontaneous preterm infants born at 34 to 36 gestational weeks weighed 1 to 1.9 SD (OR: 1.1; 95% CI: 1.1-1.2) or 2 to 2.9 SD (OR: 1.6; 95% CI: 1.5-1.7) above the expected mean more often. Conclusion: Deviation of fetal growth from the expected mean is associated with spontaneous preterm delivery.

Background: Births in midwife-led institutions may reduce the frequency of medical interventions and provide cost-effective care, while larger institutions offer medically and technically advanced obstetric care. Unplanned births outside an institution and intrapartum stillbirths have frequently been excluded in previous studies on adverse outcomes by place of birth. Objective: The objective of the study was to assess peripartum mortality by place of birth and travel time to obstetric institutions, with the hypothesis that centralization reduces institution availability but improves mortality. Study Design: This was a national population-based retrospective cohort study of all births in Norway from 1999 to 2009 (n = 648,555) using data from the Medical Birth Registry of Norway and Statistics Norway and including births from 22 gestational weeks or birthweight ≥500 g. Main exposures were travel time to the nearest obstetric institution and place of birth. The main clinical outcome was peripartum mortality, defined as death during birth or within 24 hours. Intrauterine fetal deaths prior to start of labor were excluded from the primary outcome. Results: A total of 1586 peripartum deaths were identified (2.5 per 1000 births). Unplanned birth outside an institution had a 3 times higher mortality (8.4 per 1000) than institutional births (2.4 per 1000), relative risk, 3.5 (95% confidence interval, 2.5–4.9) and contributed 2% (95% confidence interval, 1.2–3.0%) of the peripartum mortality at the population level. The risk of unplanned birth outside an institution increased from 0.5% to 3.3% and 4.5% with travel time 2 hours, respectively. In obstetric institutions the mortality rate at term ranged from 0.7 per 1000 to 0.9 per 1000. Comparable mortality rates in different obstetric institutions indicated well-functioning routines for referral. Conclusion: Unplanned birth outside an institution was associated with increased peripartum mortality and with long travel time to obstetric institutions. Structural determinants have an important impact on perinatal health in high-income countries and also for low-risk births. The results show the importance of skilled birth attendance and warrant attention from clinicians and policy makers to negative consequences of reduced access to institutions. publishedVersion