Time trends in pregnancy-related outcomes among women with type 1 diabetes mellitus, 2004-2017

OBJECTIVE

To examine time trends in US pregnant women with type 1 diabetes mellitus for maternal characteristics and pregnancy outcomes.

STUDY DESIGN

We abstracted clinical data from the medical records of 700 pregnant women from 2004 to 2017. For each time period, means and percentages were calculated. P values for trend were calculated using linear and logistic regression.

RESULTS

HbA1c in each trimester was unchanged across the analysis period. The prevalence of nephropathy decreased from 4.8% to 0% (P = 0.002). Excessive gestational weight gain increased (P = 0.01). Gestation length also increased (P = 0.01), as did vaginal deliveries (P = 0.03). There were no change in birthweight over time (P = 0.07) and the percentage of neonates with macrosomia and large for gestational age (LGA) neonates also remained unchanged.

CONCLUSION

Obstetric guideline changes may have improved gestation length and mode of delivery; however, other outcomes need more attention, including excessive gestational weight gain, macrosomia, and LGA.

Commentary on a combined approach to the problem of developing biomarkers for the prediction of spontaneous preterm labor that leads to preterm birth

INTRODUCTION

Globally, preterm birth has replaced congenital malformation as the major cause of perinatal mortality and morbidity. The reduced rate of congenital malformation was not achieved through a single biophysical or biochemical marker at a specific gestational age, but rather through a combination of clinical, biophysical and biochemical markers at different gestational ages. Since the aetiology of spontaneous preterm birth is also multifactorial, it is unlikely that a single biomarker test, at a specific gestational age will emerge as the definitive predictive test.

METHODS

The Biomarkers Group of PREBIC, comprising clinicians, basic scientists and other experts in the field, with a particular interest in preterm birth have produced this commentary with short, medium and long-term aims: i) to alert clinicians to the advances that are being made in the prediction of spontaneous preterm birth; ii) to encourage clinicians and scientists to continue their efforts in this field, and not to be disheartened or nihilistic because of a perceived lack of progress and iii) to enable development of novel interventions that can reduce the mortality and morbidity associated with preterm birth.

RESULTS

Using language that we hope is clear to practising clinicians, we have identified 11 Sections in which there exists the potential, feasibility and capability of technologies for candidate biomarkers in the prediction of spontaneous preterm birth and how current limitations to this research might be circumvented.

DISCUSSION

The combination of biophysical, biochemical, immunological, microbiological, fetal cell, exosomal, or cell free RNA at different gestational ages, integrated as part of a multivariable predictor model may be necessary to advance our attempts to predict sPTL and PTB. This will require systems biological data using "omics" data and artificial intelligence/machine learning to manage the data appropriately. The ultimate goal is to reduce the mortality and morbidity associated with preterm birth.

Fetal loss and malformations in the MONEAD study of pregnant women with epilepsy

OBJECTIVE

To examine occurrence of severe adverse fetal outcomes (SAO), including fetal loss and major congenital malformations (MCMs), in pregnant women with epilepsy (PWWE) vs healthy pregnant women (HPW).

METHODS

The Maternal Outcomes and Neurodevelopmental Effects of Antiepileptic Drugs (MONEAD) study is an NIH-funded, prospective, observational, multicenter investigation of pregnancy outcomes for both mother and child, which enrolled women December 2012 through January 2016.

RESULTS

The 351 PWWE had 365 conceptions, and 105 HPW had 109 conceptions. SAOs occurred more often in PWWE (7.9%) vs HPW (1.9%) (p = 0.025) with odds ratio (OR) 4.45 (95% confidence intervals [CI] 1.04-19.01). There were no significant differences for fetal loss (2.8% vs 0%, p = 0.126) or MCMs (5.2% vs 1.9%, p = 0.185; OR 2.86, 95% CI 0.65-12.53) individually. No fetal losses in PWWE appeared to be related to acute seizures. Outcomes were not affected by periconceptional folate, unplanned/unwanted pregnancies, prior maternal pregnancy history, or antiepileptic drug (AED) blood levels, except for an AED level effect for fetal loss that appeared to be due to polytherapy. Combined maternal or paternal family history of MCM was marginally associated with increased SAOs (p = 0.046).

CONCLUSIONS

The findings provide additional information on risks of SAOs in PWWE, assessing effects of both AED levels and periconceptional folate. Group differences in average enrollment gestational age could have affected fetal loss results. Analyses are limited by small sample sizes as the MONEAD study was not powered for these secondary outcomes. The large majority of pregnancies in women with epilepsy do not have SOAs.

Transcriptome analysis of early pregnancy vitamin D status and spontaneous preterm birth

Background

We conducted a literature review on the studies that investigated the relationship of preterm birth, including spontaneous preterm birth (sPTB), with vitamin D status. Overall, these studies demonstrated that the incidence of sPTB was associated with maternal vitamin D insufficiency in early pregnancy. However, the potential mechanisms and biological pathways are unknown.

Objectives

To investigate early pregnancy gene expression signatures associated with both vitamin D insufficiency and sPTB. We further constructed a network of these gene signatures and identified the common biological pathways involved.

Study design

We conducted peripheral blood transcriptome profiling at 10–18 weeks of gestation in a nested case-control cohort of 24 pregnant women who participated in the Vitamin D Antenatal Asthma Reduction Trial (VDAART). In this cohort, 8 women had spontaneous preterm delivery (21–32 weeks of gestation) and 17 women had vitamin D insufficiency (25-hydroxyvitamin D < 30 ng/mL). We separately identified vitamin D-associated and sPTB gene signatures at 10 to 18 weeks and replicated the overlapping signatures in the mid-pregnancy peripheral blood of an independent cohort with sPTB cases.

Result

At 10–18 weeks of gestation, 146 differentially expressed genes (25 upregulated) were associated with both vitamin D insufficiency and sPTB in the discovery cohort (FDR < 0.05). Of these genes, 43 (25 upregulated) were replicated in the independent cohort of sPTB cases and controls with normal pregnancies (P < 0.05). Functional enrichment and network analyses of the replicated gene signatures suggested several highly connected nodes related to inflammatory and immune responses.

Conclusions

Our gene expression study and network analyses suggest that the dysregulation of immune response pathways due to early pregnancy vitamin D insufficiency may contribute to the pathobiology of sPTB.

Maternal Pregnancy Hormone Concentrations in Countries with Very Low and High Breast Cancer Risk

BACKGROUND

Breast cancer rates in Asia are much lower than in Europe and North America. Within Asia, rates are lower in Mongolia than in neighboring countries. Variation in pregnancy exposure to endogenous hormone concentrations may explain the differences, but data are lacking.

METHODS

We measured maternal serum progesterone, prolactin, estradiol and estrone concentrations in the second half of pregnancy in a cross-sectional study of urban (n = 143-194 depending on the analyte) and rural (n = 150-193) Mongolian women, and U.S. women from Boston (n = 66-204). Medical records provided information on maternal and perinatal factors. Geometric mean hormones were estimated from standard linear models with the log-hormone as the dependent variable and country as the independent variable adjusted for maternal and gestational age at blood draw.

RESULTS

Mean concentrations of prolactin (5722 vs. 4648 uIU/mL; p < 0.0001) and estradiol (17.7 vs. 13.6 ng/mL; p < 0.0001) were greater in Mongolian than U.S. women, while progesterone (147 vs. 201 ng/mL; p < 0.0001) was lower. Mean hormone concentrations were similar in rural and urban Mongolian women. Results were generally similar, with additional adjustment for gravidity, parity, height, body mass index at blood draw, education and alcohol use during pregnancy, and when stratified by offspring sex or parity.

CONCLUSIONS

Mongolian women had greater concentrations of prolactin and estrogen and lower concentrations of progesterone than U.S. women, while hormone concentrations were similar in rural and urban Mongolian pregnancies.

IMPACT

These data do not support the hypothesis that estrogen concentrations in pregnant women are lower in Mongolian compared with Caucasian women.

Latent classes for chemical mixtures analyses in epidemiology: an example using phthalate and phenol exposure biomarkers in pregnant women

Latent class analysis (LCA), although minimally applied to the statistical analysis of mixtures, may serve as a useful tool for identifying individuals with shared real-life profiles of chemical exposures. Knowledge of these groupings and their risk of adverse outcomes has the potential to inform targeted public health prevention strategies. This example applies LCA to identify clusters of pregnant women from a case-control study within the LIFECODES birth cohort with shared exposure patterns across a panel of urinary phthalate metabolites and parabens, and to evaluate the association between cluster membership and urinary oxidative stress biomarkers. LCA identified individuals with: "low exposure," "low phthalates, high parabens," "high phthalates, low parabens," and "high exposure." Class membership was associated with several demographic characteristics. Compared with "low exposure," women classified as having "high exposure" had elevated urinary concentrations of the oxidative stress biomarkers 8-hydroxydeoxyguanosine (19% higher, 95% confidence interval [CI] = 7, 32%) and 8-isoprostane (31% higher, 95% CI = -5, 64%). However, contrast examinations indicated that associations between oxidative stress biomarkers and "high exposure" were not statistically different from those with "high phthalates, low parabens" suggesting a minimal effect of higher paraben exposure in the presence of high phthalates. The presented example offers verification of latent class assignments through application to an additional data set as well as a comparison to another unsupervised clustering approach, k-means clustering. LCA may be more easily implemented, more consistent, and more able to provide interpretable output.

Manganese is associated with increased plasma interleukin-1β during pregnancy, within a mixtures analysis framework of urinary trace metals

Exposure to trace metals may impact reproductive health outcomes through perturbations in maternal immune signaling molecules. We conducted a cross-sectional study of 390 pregnant women from the LIFECODES birth cohort and investigated the associations between 17 urinary metals and five immune biomarkers measured in the 3rd trimester (median 26 weeks gestation). We used linear regression to estimate pair-wise associations and applied elastic net and Bayesian kernel machine regression to identify important contributing exposures analytes as well as non-linear effects. Maternal urinary manganese, nickel, and barium were positively associated with maternal plasma interleukin-1β (IL-1β). Elastic net and Bayesian kernel machine regression identified manganese as the dominant trace metal in association with IL-1β. An interquartile range difference in manganese (0.6 μg/L) was associated with a 29 % increase in IL-1β (95 % CI: 12.4-48.2). In conclusion, trace metal exposures were associated with biomarkers of immune perturbations, and this warrants further investigation.

Variation in relationships between maternal age at first birth and pregnancy outcomes by maternal race: a population-based cohort study in the United States

OBJECTIVE

To estimate absolute risks of obstetric outcomes in the USA according to maternal age at first birth from age 15 to 45 separately by maternal race.

DESIGN AND SETTING

Population-based cohort study.

SETTING

Vital statistics Birth Cohort-Linked Birth- Infant Death Data Files and Fetal Death Data Files in the USA.

PARTICIPANTS

16 514 849 births to nulliparous women from 2004 to 2013.

OUTCOME MEASURES

We estimated absolute risks of obstetric outcomes (multiple gestations, caesarean delivery, early and late preterm birth, small for gestational age birth, stillbirth, neonatal mortality, postneonatal infant mortality) at each year of maternal age from 15 to 45 years using logistic regression in the overall population and stratified by maternal race. We modelled maternal age flexibly to allow curvilinear shapes and plotted risk curves for each outcome.

RESULTS

In the overall population, multiple gestations, caesarean delivery and stillbirth risks were lowest at young maternal ages with linear or quadratic increases with age. Curves for preterm birth, small for gestational age, neonatal mortality and postneonatal mortality were u or j shaped, with nadirs between 20 and 29 years, and elevated risks at both younger and older maternal ages. In race-stratified analyses, the shapes of the curves were generally similar across races. Risks increased for all women for all outcomes after age 30. However, increased risks at young maternal ages were most pronounced for white and Asian/Pacific Islander women, for whom young childbearing was least common. Conversely, risks at older ages were more pronounced for Black and American Indian/Alaska Native women, for whom delayed childbearing was least common.

CONCLUSION

Our findings confirm risks associated with first births to women younger than 20 and older than 30 years, provide easily interpretable risk curves and illuminate variability in these relationships across categories of maternal race in the USA.

Exposure to 17 trace metals in pregnancy and associations with urinary oxidative stress biomarkers

BACKGROUND

Exposure to some toxic metals, such as lead and cadmium, has been associated with increased oxidative stress. However less is known about other metals and metal mixtures, especially in pregnant women who are a vulnerable population.

METHODS

To study the relationship between exposure to trace metals and oxidative stress, we analyzed a panel of 17 metals and two oxidative stress biomarkers (8-isoprostane and 8-hydroxydeoxyguanosine [8-OHdG]) in urine samples collected at ~26 weeks gestation from pregnant women in Boston (n = 380). We used linear regression models to calculate percent differences and 95% confidence intervals (CI) in oxidative stress markers for an interquartile range (IQR) increase in each urinary metal with adjustment for other metals. In addition, we applied principal components analysis (PCA) and Bayesian kernel machine regression (BKMR), to examine cumulative effects (within correlated groups of exposures as well as overall) and interactions.

RESULTS

We estimated 109% (95% CI: 47, 198) higher 8-isoprostane and 71% (95% CI: 45, 102) higher 8-OHdG with an IQR increase in urinary selenium (Se). We also estimated higher 8-isoprostane (47%, 95% CI: 20.5, 79.4) and 8-OHdG (15.3%, 95% CI: 5.09, 26.5) in association with urinary copper (Cu). In our PCA, we observed higher 8-isoprostane levels in association with the "essential" PC (highly loaded by Cu, Se, and Zinc). In BKMR analyses, we also estimated higher levels of both oxidative stress biomarkers with increasing Se and Cu as well as increasing levels of both oxidative stress biomarkers in association with cumulative concentrations of urinary trace metals.

CONCLUSION

We observed higher 8-isoprostane and 8-OHdG levels in association with urinary trace metals and elements, particularly Se and Cu, in linear models and using mixtures approaches. Additionally, increasing cumulative exposure to urinary trace metals was associated with higher levels of both oxidative stress biomarkers. The beneficial effects of these compounds should be carefully questioned.

Joint impact of phthalate exposure and stressful life events in pregnancy on preterm birth

BACKGROUND

Urinary phthalate metabolites and psychosocial stress in pregnancy have each been associated with preterm birth (PTB), but no study has examined the joint impact of these two environmental exposures. We hypothesized that there would be stronger associations between phthalate exposure and PTB in mothers with higher stress in pregnancy compared to mothers with lower stress.

METHODS

We addressed this question using data from The Infant Development and the Environment Study (TIDES), a prospective birth cohort conducted at four US sites (N = 783). We examined urinary phthalate metabolite concentrations measured in samples collected from up to three trimesters of pregnancy. Mothers reported their exposure to stressful life events (SLE) in each trimester in a questionnaire administered in the third trimester. PTB was defined as delivery before 37 weeks completed gestation (n = 71, 9.1%). We examined associations between urinary phthalate metabolite concentrations (individual time points and on average) and PTB using logistic regression models adjusted for maternal race, age, pre-pregnancy body mass index, education, specific gravity, and gestational age at sample collection. In addition, we created models stratified by whether or not mothers were exposed to any or no SLE in pregnancy.

RESULTS

Summed di-2-ethylhexyl phthalate (ΣDEHP) metabolites measured in urine samples from the third trimester, but not the first trimester, were associated with an increased odds ratio (OR) of PTB (OR = 1.44, 95% confidence interval [CI] = 1.06, 1.95). In models stratified by SLE, associations between third trimester ΣDEHP concentrations and PTB were significant only for women experiencing one or more SLE during pregnancy (OR for ΣDEHP: 2.09, 95% CI: 1.29, 3.37) but not for women with no SLE during pregnancy (OR for ΣDEHP: 1.04, 95% CI: 0.66, 1.63) (p for interaction = 0.07).

CONCLUSIONS

We observed an association between urinary ΣDEHP levels and PTB that was modified by whether a mother was exposed to one or more psychosocial stressors during pregnancy. Additional research to understand the joint impacts of chemical and non-chemical exposures, with an emphasis on timing of exposure, is needed in order to advance the state of the science on how the environment influences pregnancy.

Prediction and associations of preterm birth and its subtypes with eicosanoid enzymatic pathways and inflammatory markers

Endogenous signaling molecules derived from lipids, peptides, and DNA, are important regulators of physiological processes during pregnancy. The effect of their collective impact on preterm birth (delivery < 37 weeks gestation) is understudied. We aimed to characterize the associations and predictive capacity of an extensive panel of eicosanoids, immune biomarkers, oxidative stress markers, and growth factors towards preterm birth and its subtypes. We conducted a cross-sectional study of pregnant women (recruited < 15 weeks gestation) in the LIFECODES birth cohort, which included 58 cases of preterm birth and 115 controls that delivered term. Among the cases there were 31 cases who had a spontaneous preterm birth (cases who had spontaneous preterm labor and/or preterm premature rupture of membranes) and 25 that had preterm birth associated with aberrant placentation (cases who had preeclampsia and/or intrauterine growth restriction) and 2 cases that could not be sufficiently categorized as either. We analyzed single biomarker associations with each preterm birth outcome using multiple logistic regression. Adaptive elastic-net was implemented to perform a penalized multiple logistic regression on all biomarkers simultaneously to identify the most predictive biomarkers. We then organized biomarkers into biological groups and by enzymatic pathways and applied adaptive elastic-net and random forest to evaluate the accuracy of each group for predicting preterm birth cases. The majority of associations we observed were for spontaneous preterm birth, and adaptive elastic-net identified 5-oxoeicosatetraenoic acid, resolvin D1, 5,6-epoxy-eicsatrienoic acid, and 15-deoxy-12,14-prostaglandin J2 as most predictive. Overall, lipid biomarkers performed the best at separating cases from controls compared to other biomarker categories (adaptive elastic-net AUC = 0.78 [0.62, 0.94], random forest AUC = 0.84 [0.72, 0.96]). Among the enzymatic pathways that differentiate eicosanoid metabolites, we observed the highest prediction of overall preterm birth by lipoxygenase metabolites using random forest (AUC = 0.83 [0.69, 0.96]), followed by cytochrome p450 metabolites using adaptive elastic-net (AUC = 0.74 [0.52, 0.96]). In this study we translate biological hypothesis into the language of modern machine learning. Many lipid biomarkers were highly associated with overall and spontaneous preterm birth. Among eicosanoids, lipoxygenase and cytochrome p450 products performed best in identifying overall and spontaneous preterm birth. The combination of lipid biomarkers may have good utility in clinical settings to predict preterm birth.

Average and time-specific maternal prenatal inflammatory biomarkers and the risk of labor epidural associated fever

Background

The use of labor epidural analgesia has been associated with intrapartum fever, known as labor epidural associated fever (LEAF). LEAF is most commonly non-infectious in origin and associated with elevated inflammatory cytokines.

Methods

The LIFECODES pregnancy cohort was designed to prospectively collect data to evaluate the association of maternal inflammatory biomarkers with preterm birth in women who delivered between 2007 and 2008 at Brigham and Women’s Hospital. Our secondary analysis of the data from the cohort identified 182 women for whom inflammatory biomarkers (i.e. interleukin-10, interleukin-1β, interleukin-6, tumor necrosis factor-α and C-reactive protein) collected longitudinally over four prenatal visits was available. Maternal temperature and other clinical variables were abstracted from medical records. The primary outcome, the presence of LEAF, was defined as oral temperature ≥ 38°C (≥100.4°F) after epidural analgesia initiation. Multivariable logistic regression estimated the association between inflammatory biomarker concentrations and the odds of developing an intrapartum fever after adjusting for a number of potential confounders.

Results

Women who developed LEAF were more likely to have a longer duration of epidural analgesia, whereas women who did not develop LEAF were more likely to have induced labor and positive or unknown Group B Streptococcus colonization status. However, no differences were seen by nulliparity, mode of delivery, white blood cell count at admission, baseline temperature, length of rupture of membranes and number of cervical exams performed during labor. Unadjusted and multivariable logistic regression models did not provide evidence for or exclude an association between individual maternal inflammatory biomarkers and the odds of developing LEAF, regardless of visit time-period.

Conclusion

The predictive value of maternal inflammatory biomarkers measured during early- and mid-pregnancy for the risk of developing LEAF cannot be excluded.

Environmental phthalate exposure and preterm birth in the PROTECT birth cohort

BACKGROUND

Preterm birth is a global public health issue and rates in Puerto Rico are consistently among the highest in the USA. Exposures to environmental contaminants might be a contributing factor.

METHODS

In a preliminary analysis from the Puerto Rico Testsite for Exploring Contamination Threats (PROTECT) cohort (n = 1090), we investigated the association between urinary phthalate metabolite concentrations measured at three study visits (targeted at 20, 24, and 28 weeks of gestation) individually and averaged over pregnancy with gestational age at delivery and preterm birth. We additionally assessed differences in associations by study visit and among preterm births with a spontaneous delivery.

RESULTS

Compared to women in the general USA population, urinary concentrations of metabolites of di-n-butyl phthalate (DBP) and di-isobutyl phthalate (DiBP) were higher among pregnant women in Puerto Rico. Interquartile range (IQR) increases in pregnancy-averages of urinary metabolites of DBP and DiBP were associated with shorter duration of gestation and increased odds of preterm birth. An IQR increase in mono-n-butyl phthalate (MBP), a metabolite of DBP, was associated with 1.55 days shorter gestation (95% confidence interval [CI] = -2.68, -0.42) and an odds ratio (OR) of 1.42 (95% confidence interval [CI]: 1.07, 1.88) for preterm birth. An IQR increase in mono-isobutyl phthalate (MiBP), a metabolite of DiBP, was associated with 1.16 days shorter gestation (95% CI = -2.25, -0.08) and an OR of 1.32 (95% CI: 1.02, 1.71) for preterm birth. Associations were greatest in magnitude for urinary concentrations measured at the second study visit (median 23 weeks gestation). DiBP metabolite associations were greatest in magnitude in models of spontaneous preterm birth. No associations were detected with other phthalate metabolites, including those of di-2-ethylhexyl phthalate.

CONCLUSION

Among pregnant women in the PROTECT cohort, DBP and DiBP metabolites were associated with increased odds of preterm birth. These exposures may be contributing to elevated rates of preterm birth observed in Puerto Rico.

The Preconception Period analysis of Risks and Exposures Influencing health and Development (PrePARED) consortium

BACKGROUND

Preconception health may have intergenerational influences. We have formed the PrePARED (Preconception Period Analysis of Risks and Exposures influencing health and Development) research consortium to address methodological, conceptual, and generalisability gaps in the literature.

OBJECTIVES

The consortium will investigate the effects of preconception exposures on four sets of outcomes: (1) fertility and miscarriage; (2) pregnancy-related conditions; (3) perinatal and child health; and (4) adult health outcomes.

POPULATION

A study is eligible if it has data measured for at least one preconception time point, has a minimum of selected core data, and is open to collaboration and data harmonisation.

DESIGN

The included studies are a mix of studies following women or couples intending to conceive, general-health cohorts that cover the reproductive years, and pregnancy/child cohort studies that have been linked with preconception data. The majority of the participating studies are prospective cohorts, but a few are clinical trials or record linkages.

METHODS

Data analysis will begin with harmonisation of data collected across cohorts. Initial areas of interest include nutrition and obesity; tobacco, marijuana, and other substance use; and cardiovascular risk factors.

PRELIMINARY RESULTS

Twenty-three cohorts with data on almost 200 000 women have combined to form this consortium, begun in 2018. Twelve studies are of women or couples actively planning pregnancy, and six are general-population cohorts that cover the reproductive years; the remainder have some other design. The primary focus for four was cardiovascular health, eight was fertility, one was environmental exposures, three was child health, and the remainder general women's health. Among other cohorts assessed for inclusion, the most common reason for ineligibility was lack of prospectively collected preconception data.

CONCLUSIONS

The consortium will serve as a resource for research in many subject areas related to preconception health, with implications for science, practice, and policy.

Comparison of seasonal serum 25-hydroxyvitamin D concentrations among pregnant women in Mongolia and Boston

Adequate vitamin D status during pregnancy is important for developing fetal bone strength and density and may play a role in preventing a range of skeletal and non-skeletal diseases in both mothers and children. We previously identified Mongolian women of reproductive age to have the lowest vitamin D levels yet observed in any population globally, which renders this population uniquely important in vitamin D research. In this study, we measured the seasonal distribution of 25-hydroxyvitamin D (25(OH)D) concentration in 390 healthy third trimester pregnant women living in urban and rural Mongolia using DiaSorin LIAISON and compared this distribution to that of 206 third trimester women living in Boston, USA. Also, we analyzed seasonally-independent associations between (25(OH)D) levels and selected predictors in both groups using quantile regression. Mean 25(OH)D levels were significantly higher and less seasonal in Boston (seasonal range: 27.1 ± 7.0-31.5 ± 7.7 ng/ml) than in Mongolia (seasonal range: 11.2 ± 3.9-19.2 ± 6.7 ng/ml). Adjusting for month of blood draw, higher 25(OH)D levels were significantly associated with older age, lower gravidity, lower BMI, and lack of a college or university degree among Boston participants, however, only gravidity was robust to multivariable adjustment. No assessed characteristics were independently predictive in Mongolia, likely due to universally low 25(OH)D levels and a resulting lack of between-person variation. In conclusion, vitamin D status among pregnant Mongolians is severely depressed throughout the year and should be addressed through fortification and supplementation, while in the U.S., deficiency is associated with specific characteristics targetable through supplementation.

Urinary concentrations of phenols in association with biomarkers of oxidative stress in pregnancy: Assessment of effects independent of phthalates

BACKGROUND

Maternal exposure to environmental phenols is common in pregnancy and has been linked to preterm birth, preeclampsia, and reduced fetal growth. One potential mechanism may be through increased maternal oxidative stress.

OBJECTIVE

We examined the associations between a panel of 10 urinary phenols, including dichlorophenols, benzophenone-3, parabens, triclosan and triclocarban, and bisphenol-S, and two urinary oxidative stress biomarkers, 8-hydroxydeoxyguanosine (8-OHdG) and 8-isoprostane. All exposure and outcome biomarkers were measured at 4 time points in pregnancy.

METHODS

We used repeated measures models to examine the association between repeated exposure and outcome biomarkers. Additionally, we used adaptive elastic net (AENET) to identify non-null associations accounting for the correlation structure of exposures, both for phenols and urinary phthalate metabolites that were previously associated with the oxidative stress biomarkers in our study population.

RESULTS

In adjusted repeated measures models, we observed that dichlorophenols, benzophenone-3, triclosan, and some parabens were associated with increases in both oxidative stress biomarkers. The greatest effect estimates were observed for 2,5-dichlorophenol; an interquartile range (IQR) increase in this compound was associated with a 15.2% (95% confidence interval [CI] = 11.0, 19.6) increase in 8-OHdG and a 16.7% (95% CI = 9.66, 24.2) increase in 8-isoprostane. Bisphenol-S detection was associated with a clear increase in 8-isoprostane (18.5%, 95% CI = 7.68, 30.5) but a more modest increase in 8-OHdG (6.18%, 95% CI = -0.27, 13.1). However, AENET models did not consistently select any of the phenols as predictors of 8-OHdG or 8-isoprostane when phthalate metabolites were included in the model.

CONCLUSION

Overall, urinary phenols were associated with increases in biomarkers of oxidative stress in pregnancy but either to a lesser extent, or due to correlation with, urinary phthalate metabolites.

Identifying pregnancies in insurance claims data: Methods and application to retinoid teratogenic surveillance

PURPOSE

The purpose of the study is to develop an algorithm to identify pregnancies in administrative databases and apply it to assess pregnancy rates and outcomes in women prescribed isotretinoin or tretinoin.

METHODS

Using the 2011 to 2015 Truven Health MarketScan Database, we identified pregnancies, including losses and terminations. In a cohort design, nonpregnant women filling a prescription for isotretinoin or tretinoin were matched to five women without either prescription. Women were followed for 365 days or until conception, medication discontinuation, or enrollment discontinuation ("prescription episode"). Rates of pregnancy, risks of pregnancy losses, and prevalence of infant malformations at birth were assessed by exposure.

RESULTS

We identified 2 179 192 livebirths, 8434 stillbirths, 2521 mixed births, 415 110 spontaneous abortions, 124 556 elective terminations, and 8974 unspecified abortions. There were 86 834 isotretinoin and 973 587 tretinoin episodes, matched to 5 302 105 unexposed women. Pregnancy rates were 3 (isotretinoin), 19 (tretinoin), and 34 (unexposed) per 1000 person-years. Risk of spontaneous pregnancy losses were similar; however, terminations were more common in the isotretinoin-exposed (28% [95% CI: 21%-36%]) than the tretinoin-exposed (10% [95% CI: 9%-11%]) or unexposed pregnancies (6%). Malformations occurred in 4.5% (95% CI: 3.5%-5.6%) of the tretinoin-exposed pregnancies and 4.2% of the unexposed pregnancies (adjusted odds ratio: 1.16 [95% CI: 0.85-1.58]); isotretinoin-exposed births were too few to assess malformations.

CONCLUSIONS

Administrative databases can complement risk evaluation and mitigation strategies (REMS) for known teratogens and contribute to safety surveillance for other medications. Here, isotretinoin-exposed pregnancy rates were low, but existent, and many pregnancies were terminated. Tretinoin exposure was not associated with a meaningfully elevated risk of losses or malformations as compared with unexposed pregnancies.

Urinary trace metals, maternal circulating angiogenic biomarkers, and preeclampsia: a single-contaminant and mixture-based approach

BACKGROUND

Exposures to toxic metals and deficiencies in essential metals disrupt placentation and may contribute to preeclampsia. However, effects of exposure to combinations of metals remain unknown.

OBJECTIVE

We investigated the relationship between urinary trace metals, circulating angiogenic biomarkers, and preeclampsia using the LIFECODES birth cohort.

METHODS

Urine samples collected during pregnancy were analyzed for 17 trace metals and plasma samples were analyzed for soluble fms-like tyrosine-1 (sFlt-1) and placental growth factor (PlGF). Cox proportional hazard models were used to estimate the hazard ratios (HR) of preeclampsia associated with urinary trace metals. Linear regression models were used to estimate the relationship between urinary trace metals and angiogenic biomarkers. Principal components analysis (PCA) was used to identify groups of metals and interactions between principal components (PCs) loaded by toxic and essential metals were examined.

RESULTS

In single-contaminant models, several toxic and essential metals were associated with lower PlGF and higher sFlt-1/PlGF ratio. Detection of urinary chromium was associated with preeclampsia: HR (95% Confidence Interval [CI]) = 3.48 (1.02, 11.8) and an IQR-increase in urinary selenium was associated with reduced risk of preeclampsia (HR: 0.28, 95% CI: 0.08, 0.94). Using PCA, 3 PCs were identified, characterized by essential metals (PC1), toxic metals (PC2), and seafood-associated metals (PC3). PC1 and PC2 were associated with lower PlGF levels, but not preeclampsia risk in the overall cohort.

CONCLUSIONS

Trace urinary metals may be associated with adverse profiles of angiogenic biomarkers and preeclampsia.

Demographic risk factors for adverse birth outcomes in Puerto Rico in the PROTECT cohort

Preterm birth is a major public health problem, especially in Puerto Rico where the rates are among the highest observed worldwide, reaching 18% in 2011. The Puerto Rico Testsite for Exploring Contamination Threats (PROTECT) study is an ongoing investigation of environmental factors that contribute to this condition. In the present analysis, we sought to examine common risk factors for preterm birth and other adverse birth outcomes which have not been characterized previously in this unique population. Pregnant women from the PROTECT cohort are recruited from the heavily contaminated Northern coast of the island of Puerto Rico and are free of pre-existing conditions like diabetes. We examined associations between basic demographic, behavioral (e.g., tobacco and alcohol use), and pregnancy (e.g., season and year of delivery) characteristics as well as municipality of residence in relation to preterm birth (<37 weeks gestation), postterm birth (≥41 weeks gestation), and small and large for gestational age in univariate and multivariate logistic regression models. Between 2011 and 2017, 1028 live singleton births were delivered as part of the PROTECT cohort. Of these, 107 (10%) were preterm. Preterm birth rates were higher among women with low socioeconomic status, as indicated by education level and income, and among women with high pre-pregnancy body mass index (BMI). Odds ratios of small for gestational age delivery were higher for women who reported tobacco use in pregnancy and lower for women who delivered in the hurricane and dengue season (July-October). Overall, in pregnant women residing in Puerto Rico, socioeconomic status was associated with preterm birth but few other factors were associated with this or other adverse outcomes of pregnancy. Research to understand environmental factors that could be contributing to the preterm birth epidemic in Puerto Rico is necessary.