Exercise during Pregnancy and Risk of Late Preterm Birth,Cesarean Delivery,and Hospitalizations

BackgroundFederal physical activity guidelines recommend at least 150 minutes of moderate-intensity exercise per week during pregnancy. We studied whether regular exercise during pregnancy is associated with preterm birth, cesarean delivery, and hospitalization during pregnancy.MethodsSelf-reported weekly exercise was ascertained in 3,006 women during the third trimester of pregnancy. Using multivariable logistic regression, we report the relationship between regular exercise (≥150 min/wk) and late preterm birth, cesarean delivery, and hospitalization during pregnancy, controlling for age, race, marital status, education, poverty status, prepregnancy body mass index weight category, gestational weight gain, and prepregnancy diabetes or hypertension.ResultsNearly one third of women reported meeting current federal physical activity recommendations during pregnancy. Five percent had late preterm birth, 29% had cesarean deliveries, and 20% reported hospitalization during pregnancy. In multivariable analysis, regular exercise during pregnancy was not associated with late preterm birth or hospitalization during pregnancy. Physical activity of 150 or more minutes per week was associated with reduced odds of cesarean delivery compared with less than 60 minutes per week, but the finding was not significant (adjusted odds ratio, 0.86; 95% confidence interval, 0.69–1.07).ConclusionIn the First Baby Study, physical activity was not associated with late preterm birth or hospitalizations, and may be associated with decreased odds of cesarean delivery.     

Supplementation of Omega 3 during Pregnancy and the Risk of Preterm Birth: A Systematic Review and Meta-Analysis

Preterm birth (PTB) is a major cause of neonatal death and long-term consequences for the newborn. This review aims to update the evidence about the potential benefit of pharmacological supplementation with omega 3 fatty acids during pregnancy on the incidence of PTB. The Medline, Embase, Cochrane Library and Central databases were searched until 28 June 2020 for RCTs in which omega 3 supplementation was used versus placebo to reduce PTB risk. Data from 37 trials were analyzed. We found an 11% reduction in PTB risk (RR(risk ratios), 0.89; 95% CI (confidence intervals), 0.82 to 0.97) in trials using omega 3 supplements versus placebo. Regarding early PTB (ePTB), there was a 27% reduction in the risk of ePTB (RR, 0.73; 95% CI, 0.58 to 0.92). However, after sensitivity analyses, there were no significant differences in PTB and ePTB risk (PTB RR, 0.92; 95% CI, 0.83 to 1.01, ePTB RR, 0.82; 95% CI, 0.61 to 1.09). We conclude that omega 3 supplementation during pregnancy does not reduce the risk of PTB and ePTB. More studies are required to determine the effect of omega 3 supplementations during pregnancy and the risk of detrimental fetal outcomes.     

Previous Adverse Outcome of Term Pregnancy and Risk of Preterm Birth in Subsequent Pregnancy

Objective Evaluate risk of preterm birth (PTB, < 37 completed weeks’ gestation) among a population of women in their second pregnancy with previous full term birth but other adverse pregnancy outcome. Methods The sample included singleton live born infants between 2007 and 2012 in a birth cohort file maintained by the California Office of Statewide Health Planning and Development. The sample was restricted to women with two pregnancies resulting in live born infants and first birth between 39 and 42 weeks’ gestation. Logistic regression was used to calculate the risk of PTB in the second birth for women with previous adverse pregnancy outcome including: small for gestational age (SGA) infant, preeclampsia, placental abruption, or neonatal death (≤ 28 days). Risks were adjusted for maternal factors recorded for second birth. Results The sample included 133,622 women. Of the women with any previous adverse outcome, 4.7% had a PTB while just 3.0% of the women without a previous adverse outcome delivered early (relative risk adjusted for maternal factors known at delivery 1.4, 95% CI 1.3–1.5). History of an SGA infant, placental abruption, or neonatal death increased the adjusted risk of PTB in their second birth by 1.5–3.7-fold. History of preeclampsia did not elevate the risk of a preterm birth in the subsequent birth. Conclusions for Practice The findings indicate that women with previous SGA infant, placental abruption, or neonatal death, despite a term delivery, may be at increased risk of PTB in the subsequent birth. These women may be appropriate participates for future interventions aimed at reduction in PTB.

     

Effects of Dietary Patterns during Pregnancy on Preterm Birth: A Birth Cohort Study in Shanghai

The objective of this study was to analyse representative dietary patterns during pregnancy in Shanghai and explore the effects of dietary patterns during pregnancy on preterm birth. Data were derived from the ‘Iodine Status in Pregnancy and Offspring Health Cohort’ (ISPOHC) study. Multistage, stratified random sampling was used to select survey participants from 16 districts in Shanghai, which were divided into five sampling areas; 40–70 pregnant women were selected from each area. A total of 4361 pregnant women and their offspring were involved in the study. The male-to-female ratio of the babies was 1.04:1, and the incidence of single preterm birth was 4.2%. Three dietary patterns were extracted by factor analysis: a ‘Vegetarian Pattern’, an ‘Animal Food Pattern’ (AFP), and a ‘Dairy and Egg Pattern’. These patterns explained 40.513% of the variance in dietary intake. Binary logistic regression, which was used to analyse the association between birth outcomes and scores measuring maternal dietary patterns, found only the AFP was a significant risk factor for preterm birth. Higher AFP scores were positively associated with preterm birth (Q2 vs. Q1 OR = 1.487, 95% CI: 1.002–2.207; Q3 vs. Q1 OR = 1.885, 95% CI: 1.291–2.754). After adjusting for other potential contributors, a higher AFP score was still a significant risk factor for preterm birth (Q2 vs. Q1 OR = 1.470, 95% CI: 0.990–2.183; Q3 vs. Q1 OR = 1.899, 95% CI: 1.299–2.776). The incidence of preterm birth was 4.2%. A higher score of AFP was significantly associated with a higher risk of preterm birth. The animal food intake of pregnant women should be reasonably consumed during pregnancy.     

Pregnancy Intendedness,Maternal Psychosocial Factors and Preterm Birth

Objectives: This study examined associations between reported pregnancy intendedness and several maternal psychosocial factors in relation to preterm birth (<37 weeks' completed gestation). Methods: Women were recruited into a prospective cohort study between the 24th and 29th weeks of pregnancy in central North Carolina from 1996 to 2000. Prior to delivery, participants responded to questions about pregnancy intendedness, life events impacts, depressive symptoms, and coping style. Results: Women who reported not intending their pregnancy had increased odds of reporting low, medium and high levels of perceived stress during pregnancy (OR = 1.4 [95% CI: 1.1, 1.9], OR = 2.2 [95% CI: 1.7, 2.8], and OR = 3.4 [95% CI: 2.6, 4.5], respectively, relative to very low), medium and high levels of depressive symptoms (OR = 2.2 [95% CI: 1.8, 2.9] and OR = 3.1 [95% CI: 2.4, 3.9], respectively), and medium and high levels of several coping styles. Reporting not intending the pregnancy was not associated with increased risk of preterm birth (Risk Ratio [RR] = 1.0, 95% CI: 0.8, 1.1), but reporting the highest quartile of perceived stress (RR = 1.6, 95% CI: 1.1, 2.3) and the highest tertile of distancing coping style (compared with lowest quartile) was associated with preterm birth (RR = 1.4, 95% CI: 1.1, 1.9). Interactions between pregnancy intendedness and the psychosocial variables perceived stress, depression or coping style did not modify the psychosocial variable's associations with preterm birth. Conclusions: Pregnancy intendedness remains an important concept in the reproductive health literature integrally tied to indicators of maternal mental health, but not necessarily to pregnancy outcomes.     

Nitrate in Drinking Water during Pregnancy and Spontaneous Preterm Birth: A Retrospective Within-Mother Analysis in California

Background: Nitrate is a widespread groundwater contaminant and a leading cause of drinking water quality violations in California. Associations between nitrate exposure and select adverse birth outcomes have been suggested, but few studies have examined gestational exposures to nitrate and risk of preterm birth (before 37 wk gestation).Objective: We investigated the association between elevated nitrate in drinking water and spontaneous preterm birth through a within-mother retrospective cohort study of births in California.Methods: We acquired over 6 million birth certificate records linked with Office of Statewide Health Planning and Development hospital discharge data for California births from 2000–2011. We used public water system monitoring records to estimate nitrate concentrations in drinking water for each woman’s residence during gestation. After exclusions, we constructed a sample of 1,443,318 consecutive sibling births in order to conduct a within-mother analysis. We used separate conditional logistic regression models to estimate the odds of preterm birth at 20–31 and 32–36 wk, respectively, among women whose nitrate exposure changed between consecutive pregnancies.Results: Spontaneous preterm birth at 20–31 wk was increased in association with tap water nitrate concentrations during pregnancy of 5 to <10mg/L [odds ratio (OR)=1.47; 95% confidence interval (CI): 1.29, 1.67] and ≥10mg/L (OR=2.52; 95% CI: 1.49, 4.26) compared with <5mg/L (as nitrogen). Corresponding estimates for spontaneous preterm birth at 32–36 wk were positive but close to the null for 5 to <10mg/L nitrate (OR=1.08; 95% CI: 1.02, 1.15) and for ≥10mg/L nitrate (OR=1.05; 95% CI: 0.85, 1.31) vs. <5mg/L nitrate. Our findings were similar in several secondary and sensitivity analyses, including in a conventional individual-level design.Discussion: The results suggest that nitrate in drinking water is associated with increased odds of spontaneous preterm birth. Notably, we estimated modestly increased odds associated with tap water nitrate concentrations of 5 to <10mg/L (below the federal drinking water standard of 10mg/L) relative to <5mg/L. https://doi.org/10.1289/EHP8205     

Daytime Napping and Nighttime Sleep During Pregnancy and Preterm Birth in Iran

ObjectivesThis study investigated the relationship between sleep quality during pregnancy and preterm birth.MethodsThis longitudinal study was conducted between August 2018 and May 2019. The participants were 150 pregnant women who had been referred to 7 healthcare centers in the city of Qazvin, Iran and met the inclusion criteria. The Petersburg Sleep Quality Index, the Epworth Sleepiness Scale, and 2 questions about daytime sleep status and a demographic questionnaire were administered at 14-18 weeks and 28-32 weeks of gestation. Data were analyzed using the Mann-Whitney test, the Fisher exact test, and univariate and multivariable logistic regression.ResultsIn the present study, poor sleep quality affected 84.7% of the participants at 14-18 weeks and 93.3% at 28-32 weeks of gestation. The final model for preterm birth prediction incorporated age and the Petersburg Sleep Quality Index score in the second and third trimesters. Preterm birth increased by 14% with each unit increase in age. With each unit increase in the Petersburg Sleep Quality Index score in the second and third trimesters, preterm birth increased by 42% and 28%, respectively, but the p-values of these factors were not significant.ConclusionsAlthough a significant percentage of pregnant women had poor sleep quality, no significant relationship was found between sleep quality during pregnancy and preterm birth.     

Effect of Modifiable Risk Factors on Preterm Birth: A Population Based-Cohort

Objectives The purpose of this study is to evaluate the prevalence, impact, and interaction of short interpregnancy interval (IPI), pre-pregnancy body mass index (BMI) category, and pregnancy weight gain (PWG) on the rate of preterm birth. Methods This is a population-based retrospective cohort study using vital statistics birth records from 2006 to 2011 in OH, US, analyzing singleton live births to multiparous mothers with recorded IPI (n?=?393,441). Preterm birth rate at <37 weeks gestational age was compared between the referent pregnancy (defined as normal pre-pregnancy maternal BMI, IPI of 12–24 months, and Institute of Medicine (IOM) recommended PWG) and those with short or long IPI, abnormal BMI (underweight, overweight, and obese), and high or low PWG (under or exceeding IOM recommendations). Results Only 6?% of the women in this study had a referent pregnancy, with a preterm birth rate of 7.6?% for this group. Short IPIs of <6 and 6–12 months were associated with increased rates of preterm birth rate to 12.9 and 10.4?%, respectively. Low PWG compared to IOM recommendations for pre-pregnancy BMI class was also associated with increased preterm birth rate of 13.2?% for all BMI classes combined. However, the highest rate of preterm birth of 25.2?% occurred in underweight women with short IPI and inadequate weight gain with _adjOR 3.44 (95?% CI 2.80, 4.23). The fraction of preterm births observed in this cohort that can be attributed to short IPIs is 5.9?%, long IPIs is 8.3?%, inadequate PWG is 7.5?%, and low pre-pregnancy BMI is 2.2?%. Conclusions Our analysis indicates that a significant proportion of preterm births in Ohio are associated with potentially modifiable risk factors. These data suggest public health initiatives focused on preterm birth prevention could include counseling and interventions to optimize preconception health and prenatal nutrition.     

Urinary Phthalate Metabolites in Relation to Preterm Birth in Mexico City

Background

Rates of preterm birth have been rising over the past several decades. Factors contributing to this trend remain largely unclear, and exposure to environmental contaminants may play a role.

Objective

We investigated the relationship between phthalate exposure and preterm birth.

Methods

Within a large Mexican birth cohort study, we compared third-trimester urinary phthalate metabolite concentrations in 30 women who delivered preterm (< 37 weeks of gestation) with those of 30 controls (≥ 37 weeks of gestation).

Results

Concentrations of most of the metabolites were similar to those reported among U.S. females, although in the present study mono-n-butyl phthalate (MBP) concentrations were higher and monobenzyl phthalate (MBzP) concentrations lower. In a crude comparison before correcting for urinary dilution, geometric mean urinary concentrations were higher for the phthalate metabolites MBP, MBzP, mono(3-carboxylpropyl) phthalate, and four metabolites of di(2-ethyl-hexyl) phthalate among women who subsequently delivered preterm. These differences remained, but were somewhat lessened, after correction by specific gravity or creatinine. In multivariate logistic regression analysis adjusted for potential confounders, elevated odds of having phthalate metabolite concentrations above the median level were found.

Conclusions

We found that phthalate exposure is prevalent among this group of pregnant women in Mexico and that some phthalates may be associated with preterm birth.     

Risk of Spontaneous Preterm Birth in Relation to Maternal Exposure to Intimate Partner Violence During Pregnancy in Peru

Intimate partner violence (IPV) is increasingly recognized as an important cause of maternal and perinatal morbidity. We assessed the relation between IPV and risk of spontaneous preterm birth (PTB) among Peruvian women. The study was conducted among 479 pregnant women who delivered a preterm singleton infant (<37 weeks gestation) and 480 controls (≥37 weeks gestation). Participants’ exposure to physical and emotional violence during pregnancy was collected during in-person interviews conducted after delivery and while patients were in hospital. Odds ratios (aOR) and 95 % confidence intervals (CI) were estimated from logistic regression models. The prevalence of any IPV during pregnancy was 52.2 % among cases and 34.6 % among controls. Compared with those reporting no exposure to IPV during pregnancy, women reporting any exposure had a 2.1-fold increased risk of PTB (95 % CI 1.59–2.68). The association was attenuated slightly after adjusting for maternal age, pre-pregnancy weight, and other covariates (OR = 1.99; 95 % CI 1.52–2.61). Emotional abuse in the absence of physical violence was associated with a 1.6-fold (95 % CI 1.21–2.15) increased risk of PTB. Emotional and physical abuse during pregnancy was associated with a 4.7-fold increased risk of PTB (95 % CI 2.74–7.92). Associations of similar directions and magnitudes were observed when PTB were sub-categorized according to clinical presentation or severity. IPV among pregnant women is common and is associated with an increased risk of PTB. Our findings and those of others support recent calls for coordinated global health efforts to prevent violence against women.     

Urinary Bisphenol A Levels in Young Men: Association with Reproductive Hormones and Semen Quality

Background: Few human studies have examined bisphenol A (BPA) exposure in relation to semen quality and reproductive hormones in men, and results are divergent.Objectives: We examined associations between urinary BPA concentration and reproductive hormones, as well as semen quality, in young men from the general population.Methods: Our study population consisted of 308 young men from the general population. Urinary BPA concentration was measured by isotope dilution TurboFlow-liquid chromatography–tandem mass spectrometry. We used multiple linear regression analysis to estimate associations between BPA concentration and reproductive hormones and semen quality, adjusting for confounding factors.Results: We found that 98% of the men had detectable urinary levels of BPA. Median (5th–95th percentiles) BPA concentration was 3.25 ng/mL (0.59–14.89 ng/mL). Men with BPA concentrations above the lowest quartile had higher concentrations of serum testosterone, luteinizing hormone (LH), estradiol, and free testosterone compared with the lowest quartile (p_trend ≤ 0.02). Men in the highest quartile of BPA excretion had on average 18% higher total testosterone (95% CI: 8, 28%), 22% higher LH (95% CI: 6, 39%), and 13% higher estradiol (95% CI: 4, 24%) compared with lowest quartile. Men in the highest quartile of BPA also had significantly lower percentage progressive motile spermatozoa compared with men in the lowest quartile (–6.7 percentage points, 95% CI: –11.76, –1.63). BPA was not associated with other semen parameters. Adjusting for dietary patterns did not influence the results.Conclusions: The pattern of associations between BPA and reproductive hormones could indicate an antiandrogenic or antiestrogenic effect, or both, of BPA on the hypothalamic–pituitary–gonadal hormone feedback system, possibly through a competitive inhibition at the receptor level. However, additional research is needed to confirm our findings and to further test the suggested potential mechanisms.Citation: Lassen TH, Frederiksen H, Jensen TK, Petersen JH, Joensen UN, Main KM, Skakkebaek NE, Juul A, Jørgensen N, Andersson AM. 2014. Urinary bisphenol A levels in young men: association with reproductive hormones and semen quality. Environ Health Perspect 122:478–484; http://dx.doi.org/10.1289/ehp.1307309     

Medical and Psychosocial Risk Profiles for Low Birthweight and Preterm Birth

ObjectivesLow birthweight and preterm birth are risk factors for infant mortality and persistent problems. This study uses representative data to assess whether distinct latent profiles of co-occurring medical and psychosocial factors have implications for preterm birth and low birthweight.MethodsData are from the Pregnancy Risk Assessment Monitoring System, a cross-sectional survey constituting representative data on pregnancies from 2012 to 2013. Latent class analysis derived classes of pregnant women potentially at risk for low birthweight and/or preterm birth.ResultsLatent class analysis identified five homogenous profiles of interrelated psychosocial and medical factors. Risk was greatest for the profile marked by high rates of medical factors, followed by a high risk for a profile marked by a combination of very low income and psychosocial factors. Two profiles involving low income and very low income also indicated greater risk for adverse birth outcomes related to socioeconomic status.ConclusionsMore attention should be paid to screening for and addressing psychosocial risk in concert with prenatal care. Women who show high-risk profiles can be monitored and supported by an interdisciplinary care team, when warranted.     

Second Births to Teenage Mothers: Risk Factors For Low Birth Weight and Preterm Birth

CONTEXT: Teenagers are more likely than older women to have a low-birth-weight infant or a preterm birth, and the risks may be particularly high when they have a second birth. Identifying predictors of these outcomes in second teenage births is essential for developing preventive strategies.
METHODS: Birth certificate data for 1993–2002 were linked to identify second births to Milwaukee teenagers. Predictors of having a low-birth-weight second infant or a preterm second birth were identified using logistic regression.
RESULTS: The same proportion of first and second infants were low-birth-weight (12%), but second births were more likely than first births to be preterm (15% vs. 12%). In analyses that adjusted for demographic, pregnancy and behavioral characteristics, the odds that a second infant was low-birth-weight or preterm were elevated if the mother smoked during pregnancy (odds ratios, 2.2 and 1.9, respectively), had inadequate prenatal weight gain (1.8 and 1.4), had an interpregnancy interval of less than 18 months (1.6–2.9 and 1.4–2.3) or was black (2.7 and 1.7). Women who had received an adequate level of prenatal care had reduced odds of both outcomes (0.6 and 0.4). Women younger than 16 also had increased odds of having a low-birth-weight second infant. Further adjustment for socioeconomic characteristics yielded largely the same results. In addition, women who were unmarried or did not identify a father were at increased risk of both outcomes (1.5 for each), and poor women were at risk of having a low-birth-weight infant (1.3).
CONCLUSIONS: Predictors of poor birth outcomes include modifiable behaviors. Prenatal interventions addressing these behaviors could help improve outcomes.     

Polycarbonate Bottle Use and Urinary Bisphenol A Concentrations

Background

Bisphenol A (BPA) is a high-production-volume chemical commonly used in the manufacture of polycarbonate plastic. Low-level concentrations of BPA in animals and possibly in humans may cause endocrine disruption. Whether ingestion of food or beverages from polycarbonate containers increases BPA concentrations in humans has not been studied.

Objectives

We examined the association between use of polycarbonate beverage containers and urinary BPA concentrations in humans.

Methods

We conducted a nonrandomized intervention of 77 Harvard College students to compare urinary BPA concentrations collected after a washout phase of 1 week to those taken after an intervention week during which most cold beverages were consumed from polycarbonate drinking bottles. Paired t-tests were used to assess the difference in urinary BPA concentrations before and after polycarbonate bottle use.

Results

The geometric mean urinary BPA concentration at the end of the washout phase was 1.2 μg/g creatinine, increasing to 2.0 μg/g creatinine after 1 week of polycarbonate bottle use. Urinary BPA concentrations increased by 69% after use of polycarbonate bottles (p < 0.0001). The association was stronger among participants who reported ≥ 90% compliance (77% increase; p < 0.0001) than among those reporting < 90% compliance (55% increase; p = 0.03), but this difference was not statistically significant (p = 0.54).

Conclusions

One week of polycarbonate bottle use increased urinary BPA concentrations by two-thirds. Regular consumption of cold beverages from polycarbonate bottles is associated with a substantial increase in urinary BPA concentrations irrespective of exposure to BPA from other sources.