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Vitamin B12 (hereafter referred to as B12) deficiency in pregnancy is prevalent and has been associated with both lower birth weight (birth weight <2,500 g) and preterm birth (length of gestation <37 weeks). Nevertheless, current evidence is contradictory. We performed a systematic review and a meta-analysis of individual participant data to evaluate the associations of maternal serum or plasma B12 concentrations in pregnancy with offspring birth weight and length of gestation. Twenty-two eligible studies were identified (11,993 observations). Eighteen studies were included in the meta-analysis (11,216 observations). No linear association was observed between maternal B12 levels in pregnancy and birth weight, but B12 deficiency (<148 pmol/L) was associated with a higher risk of low birth weight in newborns (adjusted risk ratio = 1.15, 95% confidence interval (CI): 1.01, 1.31). There was a linear association between maternal levels of B12 and preterm birth (per each 1-standard-deviation increase in B12, adjusted risk ratio = 0.89, 95% CI: 0.82, 0.97). Accordingly, B12 deficiency was associated with a higher risk of preterm birth (adjusted risk ratio = 1.21, 95% CI: 0.99, 1.49). This finding supports the need for randomized controlled trials of vitamin B12 supplementation in pregnancy., (© The Author 2017. 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.)

Purpose: To estimate whether low-to-moderate prenatal alcohol exposure is associated with selected birth outcomes., Methods: Low-to-moderate prenatal alcohol drinking and effects on low birthweight, preterm delivery, intrauterine growth restriction, and selected neonatal outcomes were evaluated among 4496 women and singleton infants. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using multivariable logistic regression, controlling for confounding variables., Results: Early pregnancy drinking was associated with reduced odds of low birthweight, OR, 0.66 (95% CI, 0.46-0.96) and birth length less than 10th percentile, OR, 0.74 (95% CI, 0.56-0.97). Drinking during the first 3 months showed lower odds for birth length and head circumference less than 10th percentile, OR, 0.56 (95% CI, 0.36-0.87) and OR, 0.69 (95% CI, 0.50-0.96), respectively. Third trimester drinking was associated with lower odds for low birthweight, OR, 0.56 (95% CI, 0.34-0.94) and preterm delivery, OR, 0.60 (95% CI, 0.42-0.87)., Conclusions: Our results suggest low-to-moderate alcohol exposure during early and late gestation is not associated with increased risk of low birthweight, preterm delivery, intrauterine growth restriction, and most selected perinatal outcomes., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Context: The increasing prevalence of childhood asthma has been associated with low microbial exposure as described by the hygiene hypothesis., Objective: We sought to evaluate the evidence of association between antibiotic exposure during pregnancy or in the first year of life and risk of childhood asthma., Methods: PubMed was systematically searched for studies published between 1950 and July 1, 2010. Those that assessed associations between antibiotic exposure during pregnancy or in the first year of life and asthma at ages 0 to 18 years (for pregnancy exposures) or ages 3 to 18 years (for first-year-of-life exposures) were included. Validity was assessed according to study design, age at asthma diagnosis, adjustment for respiratory infections, and consultation rates., Results: For exposure in the first year of life, the pooled odds ratio (OR) for all studies (N = 20) was 1.52 (95% confidence interval [CI]: 1.30-1.77). Retrospective studies had the highest pooled risk estimate for asthma (OR: 2.04 [95% CI: 1.83-2.27]; n = 8) compared with database and prospective studies (OR: 1.25 [95% CI: 1.08-1.45]; n = 12). Risk estimates for studies that adjusted for respiratory infections (pooled OR: 1.16 [95% CI: 1.08-1.25]; n = 5) or later asthma onset (pooled OR for asthma at or after 2 years: OR: 1.16 [95% CI: 1.06-1.25]; n = 3) were weaker but remained significant. For exposure during pregnancy (n = 3 studies), the pooled OR was 1.24 (95% CI: 1.02-1.50)., Conclusions: Antibiotics seem to slightly increase the risk of childhood asthma. Reverse causality and protopathic bias seem to be possible confounders for this relationship.

We demonstrated that asthma remains a common condition among pregnant women and that the prevalence of self-reported asthma in the United States is between 8.4% and 8.8%. In addition, approximately 4.1% of all pregnant women experienced an asthma attack in the previous year. Prevalence rates in other countries seem to be higher or substantially lower; however, further characterization of international trends using nationally representative data is needed. Data from a large prospective cohort study in the northeastern United States and national data demonstrate continued opportunities for population-level improvement in well-managed asthma during pregnancy. Finally, asthma diagnosis and asthma control seem to differ by population characteristics (eg, age, race/ethnicity, socio-economic status), and further research and clinical involvement are needed to ad-dress potentially systematic variation in reporting and management of the disease.

Although pregnancy is purported to affect maternal asthma, the literature has not been reviewed systematically. The purpose of this systematic review was to determine, among pregnant women with asthma, whether pregnancy and stage of pregnancy influence maternal asthma severity. Six electronic databases were searched in January 2003 for prospective studies of currently asthmatic, pregnant women who were enrolled before the third trimester and assessed with objective measures of asthma severity or validated severity scales. Three studies reported 54 pregnant women with asthma who met the inclusion criteria. The most valid study indicated that bronchial hyperresponsiveness to methacholine improved between preconception and pregnancy in 69% of the women, although it deteriorated in 31% of the women. Further, this improvement peaked in the second trimester, reverted after delivery, and was greatest among those women who were most hyperresponsive initially. Lung function also showed a trend towards improvement during pregnancy that was not significant. Large, well-conducted population-based studies that explore different aspects of asthma severity are needed to substantiate these preliminary results.

Objective: To prospectively examine in pregnant women whether asthma or asthma therapy influenced preterm delivery, intrauterine grown restriction (IUGR), or birthweight., Methods: We enrolled 873 pregnant women with a history of asthma, of whom 778 experienced asthma symptoms or took medication, and 1333 women with no asthma history, including 884 women with neither asthma diagnosis nor symptoms and 449 with symptoms but no diagnosis. Asthma symptoms, medication, and severity were classified according to 2002 Global Initiative for Asthma guidelines., Results: Preterm delivery was not associated with asthma diagnosis, severity, or symptoms but was associated with use of controller medications, independent of symptoms, specifically oral steroids and theophylline. Gestation was reduced by 2.22 weeks in women using oral steroids daily (P =.001) and 1.11 weeks after theophylline (P =.002). We observed a 24% (5-47%) increased risk for IUGR with each increased symptom step, which increased further in symptomatic women with no asthma diagnosis (31%, 4-65%) compared with women with neither asthma nor symptoms., Conclusions: We found no effect of asthma symptoms or severity on preterm delivery but observed increased risks associated with use of oral steroid and theophylline. Intrauterine growth restriction was associated with asthma severity, which possibly reflects a hypoxic fetal effect. Women with asthma symptoms but no diagnosis were at particular risk of undermedication and delivering IUGR infants. These observations support guidelines that advocate active management of pregnant patients with mild or moderate asthma with beta(2) agonists, with oral steroids added only if severity increases. Symptomatic patients without an asthma diagnosis might need to be equally managed.

Purpose: Asthma is a major complication of pregnancy, but there are currently no reliable national estimates for the United States of asthma prevalence in pregnancy or in the childbearing years., Methods: The prevalence of asthma among pregnant women and all childbearing-aged women was estimated and examined by age group using the National Health Interview Survey (NHIS), 1997-2000, the Behavioral Risk Factor Surveillance System (BRFSS), 2000-2001, and the Third National Health and Nutrition Examination Survey (NHANES III), 1988-1994. Time trends were explored using NHANES II (1976-1980) and NHANES III (1988-1994)., Results: Asthma was estimated to affect from 88,573 to 190,650 pregnant women between 1997 and 2001, or approximately 3.7% to 8.4% of pregnant women in the United States. A slightly lower estimate of 3.2% was obtained for the period between 1988 and 1994. Among adult women of childbearing age, a two-fold increase in asthma from 2.9% to 5.8% occurred between 1976-1980 and 1988-1994. Among women aged 18 to 24, the increase was three-fold, from 1.8% to 6.0%., Conclusion: The prevalence of asthma during pregnancy may be higher than previously estimated and appears to be continuing to increase.

Background: Close to one in ten individuals worldwide is born preterm, and it is important to understand patterns of long-term health and mortality in this group. This study assesses the relationship between gestational age at birth and early adult mortality both in a nationwide population and within sibships. The study adds to existing knowledge by addressing selected causes of death and by assessing the role of genetic and environmental factors shared by siblings. Methods: Study population was all Norwegian men and women born from 1967 to 1997 followed using nation-wide registry linkage for mortality through 2011 when they were between 15 and 45 years of age. Analyses were performed within maternal sibships to reduce variation in unobserved genetic and environmental factors shared by siblings. Specific outcomes were all-cause mortality and mortality from cardiovascular diseases, cancer and external causes including accidents, suicides and drug abuse/overdoses. Results: Compared with a sibling born in week 37–41, preterm siblings born before 34 weeks gestation had 50% increased mortality from all causes (adjusted Hazard Ratio (aHR) 1.54, 95% confidence interval (CI) 1.17, 2.03). The corresponding estimate for the entire population was 1.27 (95% CI 1.09, 1.47). The majority of deaths (65%) were from external causes and the corresponding risk estimates for these deaths were 1.52 (95% CI 1.08, 2.14) in the sibships and 1.20 (95% CI 1.01, 1.43) in the population. Conclusion: Preterm birth before week 34 was associated with increased mortality between 15 and 45 years of age. The results suggest that increased premature adult mortality in this group is related to external causes of death and that the increased risks are unlikely to be explained by factors shared by siblings. [ABSTRACT FROM AUTHOR]

Background: It remains unclear whether fine particulate (PM2.5) exposure affects risk of preterm birth and prelabor rupture of membranes. Unmeasured, poorly measured, and undiscovered individual-level confounders might have introduced bias into past studies that relied on between-women comparisons.Methods: This was a longitudinal study of preterm birth and prelabor rupture of membranes in Rochester, NY, 2004-2012 (N = 3,264 women, N = 7,121 singleton births). We used conditional logistic regression to match pregnancies to the same woman and estimate the odds of each outcome associated with average PM2.5 concentrations during each trimester and whole pregnancy.Results: For preterm birth, adjusted odds ratios (95% confidence interval) for 1 μg/m increase in PM2.5 in the first trimester, second trimester, third trimester, and whole pregnancy were 1.11 (1.04, 1.18), 1.09 (1.02, 1.16), 1.06 (1.00, 1.13), and 1.17 (1.07, 1.28), respectively. For prelabor rupture of membranes, corresponding odds ratios were 1.00 (0.97, 1.04), 0.99 (0.96, 1.02), 0.99 (0.96, 1.03), and 0.99 (0.94, 1.04), respectively.Conclusion: Risk of preterm birth was greater for pregnancies with elevated PM2.5 exposure than other pregnancies to the same women at lower exposure. We did not observe an association between PM2.5 concentrations and prelabor rupture of membranes. [ABSTRACT FROM AUTHOR]

Objective: To assess whether folic acid intake during the first trimester of pregnancy is related to pregnancy outcomes preeclampsia, low birth weight or preterm birth.Study Design: Prospective cohort study of 3647 women who were followed from the first trimester of pregnancy. Detailed information on quantity of folic acid intake before and during the first three months of pregnancy was recorded. Pregnancy outcome data were abstracted from obstetric records.Results: Lean mothers who used folic acid supplementation the month before pregnancy had a 40% reduced risk of developing preeclampsia. The adjusted odds ratio (OR) with 95% confidence intervals (95%CI) for preeclampsia in lean mothers (BMI<25) who used folic acid supplements the month before pregnancy was 0.6 (95% CI 0.4-1.0). Obese mothers who used folic acid supplementation in the first trimester had an increased, but not statistically significant risk for preterm birth (adjusted OR 1.9 with 95% CI 0.9-4.0). There were no significant associations between folic acid supplementation and low birth weight.Conclusion: Our study supports a possible protective effect of folate intake in early pregnancy on preeclampsia in lean mothers. There was no support for any beneficial effect of folic acid use on preterm birth or low birth weight, and we found no evidence of any harmful effects of folate use for the outcomes included in our study. [ABSTRACT FROM AUTHOR]

This study estimates the effect of maternal infections during pregnancy on childhood asthma. One-thousand four-hundred and twenty-eight pregnant women were prospectively followed using structured interviews and chart review until their child’s 6th year of life. Infections were identified from outpatient and hospital visits. Childhood asthma was defined as physician diagnosis with symptoms at age six. Adjusted odds ratios were calculated from multivariable logistic regression models. Six-hundred and thirty-five women experienced an infection during pregnancy. Among antepartum infections, maternal urinary tract infections were significantly associated with childhood asthma (aOR 1.60, 95 % CI 1.12–2.29). Chorioamnionitis and maternal group beta streptococcus colonization were not significantly associated with an increased risk in childhood asthma. This study found an increased risk of asthma in children of women diagnosed with urinary tract infections during pregnancy, while other maternal infections did not increase the risk. [ABSTRACT FROM AUTHOR]

A genome-wide association study was undertaken to identify maternal single nucleotide polymorphisms (SNPs) and copy-number variants (CNVs) associated with pre-eclampsia. Case-control analysis was performed on 1070 Afro-Caribbean (n = 21 cases and 1049 controls) and 723 Hispanic (n = 62 cases and 661 controls) mothers and 1257 mothers of European ancestry (n = 50 cases and 1207 controls) from the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) study. European ancestry subjects were genotyped on Illumina Human610-Quad and Afro-Caribbean and Hispanic subjects were genotyped on Illumina HumanlM-Duo BeadChip microarrays. Genome-wide SNP data were analyzed using PLINK. CNVs were called using three detection algorithms (GNOSIS, PennCNV, and QuantiSNP), merged using CNVision, and then screened using stringent criteria. SNP and CNV findings were compared to those of the Study of Pregnancy Hypertension in Iowa (SOPHIA), an independent pre-eclampsia case-control dataset of Caucasian mothers (n = 177 cases and 116 controls). A list of top SNPs were identified for each of the HAPO ethnic groups, but none reached Bonferroni-corrected significance. Novel candidate CNVs showing enrichment among pre-eclampsia cases were also identified in each of the three ethnic groups. Several variants were suggestively replicated in SOPHIA. The discovered SNPs and copy-number variable regions present interesting candidate genetic variants for pre-eclampsia that warrant further replication and investigation. [ABSTRACT FROM AUTHOR]

Few studies of preeclampsia have assessed physical activity level, yet recent evidence suggests that the pathologic mechanisms in preeclampsia are similar to those in cardiovascular disease, for which physical activity is shown to be protective. The authors assessed the independent and combined effects of work and regular leisure-time physical activity (LTPA) during early pregnancy on risk of de novo preeclampsia (n = 44) and gestational hypertension (n = 172) among women recruited from 13 obstetric practices in the New Haven, Connecticut, area between 1988 and 1991. Control subjects were normotensive throughout pregnancy (n = 2,422). Information on time at work spent sitting, standing, and walking and on LTPA before and during pregnancy was collected via face-to-face interviews. Logistic regression analyses suggested that women who engaged in any regular LTPA regardless of caloric expenditure (adjusted odds ratio (aOR) = 0.66, 95% confidence interval (CI): 0.35, 1.22), were unemployed (aOR = 0.64, 95% CI: 0.21, 2.00), or had nonsedentary jobs (aOR = 0.71, 95% CI: 0.37, 1.36) were at decreased risk of preeclampsia. Analyses of gestational hypertension showed no indication of a protective effect of workplace activity, LTPA, or unemployment. Consistent with other studies, these data suggest that regular physical activity during pregnancy may reduce preeclampsia risk. [ABSTRACT FROM AUTHOR]