Temporal Association Between Interracial Couples and Odds of Low Birth Weight Infants: Trends in National Vital Statistics Data from 1971 to 2016.

Our study explores the temporal association between low birth weight (LBW) infants and the increasing population prevalence of interracial relationships. Our hypothesis was that the odds of LBW would decrease as the population prevalence of interracial relationships increased. National Center for Health Statistics Natality data for 1971-2016 was analyzed. LBW was defined as birth weight less than 2500 gm. We restricted our analyses to singleton births by White and Black mothers with reported White or Black partners of the neonate. Logistic regression was used to calculate the odds ratios of LBW, both unadjusted and adjusted for maternal education and parental ages. The proportion of couples coded as interracial increased annually from 0.36% in 1971 to 3.86% in 2016 for White mothers and 0.59% to 8.63% for Black mothers during the same period. In each year the odds ratio of LBW was significant. As the proportion of White mothers with Black partners increased, their odds of LBW declined (OR1.75 to 1.30, p < 0.001). The odds ratio of LBW among Black mothers with White partners did not change and remained stable between 0.70 and 0.80 (p = 0.22) over the same time period. As the annual proportion of White mothers with Black partners increased, their odds of LBW decreased when compared to White couples. Black mothers with White partners did not exhibit a similar change when compared to Black couples, with the odds ratio of LBW remaining stable.

Serum antioxidant vitamin concentrations and oxidative stress markers associated with symptoms and severity of premenstrual syndrome: a prospective cohort study.

BACKGROUND: It has been suggested that premenstrual syndrome (PMS) may derive from either elevated oxidative stress or reduced antioxidant vitamin levels in the body; however, these relationships have been minimally studied in a large cohort of healthy women. Our objective was to estimate the association between serum concentrations of antioxidant vitamins (A, C, and E) and markers of oxidative stress (F2-isoprostane) with symptoms and severity of PMS. METHODS: The BioCycle study was a prospective cohort study following 259 healthy premenopausal women aged 18-44 years for up to 2 menstrual cycles. Frequency/severity of 20 PMS symptoms were assessed via questionnaires 4 times/cycle, and antioxidant vitamins and oxidative stress biomarkers were measured up to 8 times/cycle to correspond with specific cycle phases. Generalized linear models were used to estimate associations between mean antioxidant concentrations and oxidative stress biomarkers with PMS symptoms and severity; linear mixed models were used to evaluate associations with symptom severity scores within groups (e.g. depression, cravings, pain). RESULTS: Higher concentrations of serum antioxidant vitamins were largely not associated with prevalence or severity of PMS symptoms. Though a few associations were observed, only associations between mean γ-tocopherol and decreased odds of swelling of the hands/feet survived adjustment for multiple comparisons (OR 0.33, 95% CI 0.16, 0.65, per ug/dL). However, F2-isoprostanes were associated with prevalence and severity of several symptoms specifically related to depression and cravings (depression score ß = 0.07, 95% CI 0.02, 0.12, per 10 ug/dL; cravings score ß = 0.16, 95% CI 0.10, 0.22, per 10 ug/dL), as well as with classification of PMS severity (OR 1.07, 95% CI 1.01, 1.14, per 10 pg/dL), with these associations surviving adjustment for false discovery rate. CONCLUSIONS: F2-isoprostanes, but not antioxidant vitamins, were associated with select PMS symptoms, as well as symptom and severity categories. Specific symptom relationships merit further research.

Adiposity is associated with anovulation independent of serum free testosterone: A prospective cohort study.

BACKGROUND: Obesity, a body mass index (BMI) ≥30 kg/m2 , is linked to infertility, potentially through a greater risk of anovulation due to elevated androgens. Yet, previous studies have not directly assessed the impact of adiposity, or body fat, on anovulation in the absence of clinical infertility. OBJECTIVE: To characterise the associations between adiposity and anovulation among women menstruating on a regular basis. METHODS: Women from the EAGeR trial (n = 1200), a randomised controlled trial of low-dose aspirin and pregnancy loss among women trying to conceive, were used to estimate associations between adiposity and incident anovulation. Participants completed baseline questionnaires and anthropometry, and provided blood specimens. Women used fertility monitors for up to six consecutive menstrual cycles, with collection of daily first morning voids for hormone analysis in the first two menstrual cycles for prospective assessment of anovulation. Anovulation was assessed by urine pregnanediol glucuronide or luteinising hormone concentration or the fertility monitor. Weighted mixed-effects log-binomial regression was used to estimate associations between measures of adiposity and incident anovulation, adjusted for free (bioavailable) testosterone, anti-Mullerian hormone (AMH), serum lipids, and demographic and life style factors. RESULTS: 343 (28.3%) women experienced at least one anovulatory cycle. Anovulation risk was higher per kg/m2 greater BMI (relative risk [RR] 1.03, 95% confidence interval (CI) 1.01, 1.04), cm waist circumference (RR 1.01, 95% CI 1.00, 1.02), mm subscapular skinfold (RR 1.02, 95% CI 1.01, 1.03), and mm middle upper arm circumference (RR 1.04, 95% CI 1.01, 1.06) adjusted for serum free testosterone, AMH, lipids, and other factors. CONCLUSIONS: Adiposity may be associated with anovulation through pathways other than testosterone among regularly menstruating women. This may account in part for reported associations between greater adiposity and infertility among women having menstrual cycles regularly. Understanding the association between adiposity and anovulation might lead to targeted interventions for preventing infertility.

Family history of autoimmune disease in relation to time-to-pregnancy, pregnancy loss, and live birth rate.

Several autoimmune conditions have adverse effects on reproductive outcomes, but the relationship between family history of autoimmune disease in women without these conditions and pregnancy is uncertain. The objective of this study was to determine if there is an association between a family history of an autoimmune condition and time-to-pregnancy (TTP), pregnancy loss, and live birth. This was a prospective cohort study from a RCT of 1228 adult women ages 18-40, who were healthy, had no history of infertility, were actively attempting to conceive, and had one or two prior pregnancy losses. Of these, 1172 women had data available regarding family history of autoimmune conditions. Women with an affected first-degree relative had similar TTP when compared to those without a FHx (fecundability odds ratio 0.90, 95% confidence interval [CI] 0.70, 1.15). Women with an affected first-degree relative had a lower likelihood of live birth (relative risk [RR] 0.83, 95% CI 0.69, 0.99). Among women who achieved pregnancy, FHx of autoimmune disease was associated with a higher likelihood of pregnancy loss (RR 1.49, 95% CI 1.10, 2.03). Women who had a first-degree relative with an autoimmune disease had a similar TTP as unaffected women but a lower likelihood of live birth and higher risk of pregnancy loss. This information may encourage clinicians to evaluate women with a family history of autoimmune conditions prior to pregnancy and highlights the need for further studies to ascertain the effects of autoimmunity and pregnancy.

Associations Between Preconception Plasma Fatty Acids and Pregnancy Outcomes.

BACKGROUND: Although fatty acids are involved in critical reproductive processes, the relationship between specific fatty acids and fertility is uncertain. We investigated the relationship between preconception plasma fatty acids and pregnancy outcomes. METHODS: We included 1,228 women attempting pregnancy with one to two previous pregnancy losses from the EAGeR trial (2007-2011). Plasma fatty acids were measured at baseline. We used log-binomial regression to assess associations between fatty acids and pregnancy, pregnancy loss, and live birth, adjusting for age, race, smoking, BMI, physical activity, income, parity, treatment arm, and cholesterol. RESULTS: Although total saturated fatty acids (SFAs) were not associated with pregnancy outcomes, 14:0 (myristic acid; relative risk [RR] = 1.10, 95% confidence interval [CI] = 1.02, 1.19, per 0.1% increase) and 20:0 (arachidic acid; RR = 1.05, 95% CI = 1.01, 1.08, per 0.1% increase) were positively associated with live birth. Findings suggested a positive association between total monounsaturated fatty acids (MUFAs) and pregnancy and live birth and an inverse association with loss. Total polyunsaturated fatty acids (PUFAs) were associated with lower probability of pregnancy (RR = 0.97, 95% CI = 0.95, 1.00) and live birth (RR = 0.96, 95% CI = 0.94, 0.99), and increased risk of loss (RR = 1.10, 95% CI = 1.00, 1.20), per 1% increase. Trans fatty acids and n-3 fatty acids were not associated with pregnancy outcomes. CONCLUSIONS: Preconception total plasma MUFAs were positively associated with pregnancy and live birth. PUFAs were inversely associated with pregnancy outcomes. Specific SFAs were associated with a higher probability of live birth. Our results suggest that fatty acids may influence pregnancy outcomes.

Preconception Leptin and Fecundability, Pregnancy, and Live Birth Among Women With a History of Pregnancy Loss.

CONTEXT: With the increase of obesity, it is imperative to understand the neuroendocrine mechanisms, including the neuroendocrine hormone leptin, by which obese or overweight women are at increased risk for subfertility and infertility. OBJECTIVE: The objective was to examine associations between preconception serum leptin concentrations, fecundability, pregnancy, and live birth. DESIGN: Secondary analysis of a prospective cohort among women with prior pregnancy losses. SETTING: The study was conducted at four US medical centers (2006 to 2012). INTERVENTION: Not available. MATERIALS AND METHODS: Preconception serum leptin concentrations were measured at baseline, and women were followed for up to six menstrual cycles, and throughout pregnancy if they conceived. Discrete Cox proportional hazard regression models were used to assess fecundability odds ratios (FORs) and log-binomial regression to estimate risk ratios (RRs) for pregnancy and live birth. Models were adjusted for age, physical activity, treatment arm, and adiposity, either by measured waist-to-hip ratio or body mass index (BMI). RESULTS: High leptin concentrations were associated with decreased fecundability (FOR 0.72, 95% CI 0.58, 0.90), reduced risk of pregnancy (RR 0.87, 95% CI 0.78, 0.96) and live birth (RR 0.76, 95% CI 0.65, 0.89) comparing the upper to the lower tertile. However, adjustment for BMI in lieu of waist-to-hip ratio nullified observed associations. CONCLUSIONS: In women with a history of pregnancy loss, relations between higher preconception leptin and fecundability were attenuated after adjustment for BMI, although not after adjustment for other markers of adiposity. Leptin may serve as a complementary marker of adiposity for assessment of obesity and reproductive outcomes.

Preconception Plasma Phospholipid Fatty Acids and Fecundability.

Context: Fatty acids (FAs) are important for reproductive processes, including steroidogenesis, though associations with fecundability, as measured by time to pregnancy (TTP), are unclear. Objective: To investigate the relationship between preconception plasma phospholipid FA (PPFA) levels and time to human chorionic gonadotropin-pregnancy among women with prior pregnancy loss. Design, Setting, and Participants: Prospective cohort of 1228 women attempting pregnancy (aged 18 to 40 years, with one or two prior pregnancy losses) followed for up to six cycles at four US university medical centers during 2006 to 2012. PPFA levels were measured at baseline. Main Outcome Measures: Associations with fecundability overall and by body mass index (BMI) group after adjusting for confounders were estimated using fecundability odds ratios (FORs) and 95% CIs. False discovery rate (FDR) was used to account for multiple comparisons. Results: Monounsaturated fatty acids (MUFAs) were associated with increased fecundability or shorter TTP [FOR, 1.08 (95% CI, 1.01 to 1.16) per unit increase in percentage of total FAs], whereas polyunsaturated fatty acids (PUFAs) were associated with decreased fecundability or longer TTP [FOR, 0.95 (95% CI, 0.91 to 1.00) per 1% change], though associations only remained significant after FDR adjustment among women with BMI <25 kg/m2. Saturated FA and trans FA were not associated with fecundability. Omega-3 FAs and omega-6 linoleic acid were not associated with fecundability. Conclusion: We observed associations between preconception MUFA and PUFA levels and fecundability among women with normal BMI, highlighting the importance of FA composition among normal-weight women with prior pregnancy loss.

Association of preconception serum 25-hydroxyvitamin D concentrations with livebirth and pregnancy loss: a prospective cohort study.

BACKGROUND: Vitamin D deficiency during pregnancy is associated with adverse pregnancy outcomes, although the association between preconception vitamin D concentrations and livebirth is unknown. We aimed to assess the association between preconception vitamin D and pregnancy outcomes among women with proven fecundity. METHODS: We did a secondary analysis of a prospective cohort from the block-randomised, double-blind, placebo-controlled EAGeR trial. Women aged 18-40 years with one to two previous pregnancy losses were recruited from June 15, 2007, to July 15, 2011, at four clinical sites in the USA and followed up for up to six menstrual cycles while attempting pregnancy and throughout pregnancy if they conceived. Serum 25-hydroxyvitamin D was measured at baseline (preconception) and 8 weeks of gestation. Outcomes of interest included clinical pregnancy, time to pregnancy, pregnancy loss, and livebirths. Risk ratios (RRs) and 95% CIs for livebirths, pregnancy, and pregnancy loss were estimated with weighted log-binomial regression. To assess time to pregnancy, we used discrete time Cox proportional hazards models to calculate fecundability odds ratios (FORs) with 95% CIs. EAGeR is registered with ClinicalTrials.gov, number NCT00467363. FINDINGS: 1191 women had available data on preconception 25-hydroxyvitamin D concentrations. 555 (47%) women were classified as having sufficient concentrations (≥75 nmol/L) and 636 (53%) as having insufficient concentrations (<75 nmol/L). Women with sufficient preconception 25-hydroxyvitamin D were more likely to achieve clinical pregnancy (adjusted RR 1·10 [1·01-1·20]) and livebirth (1·15 [95% CI 1·02-1·29]) than were women with insufficient concentrations. Among women who achieved pregnancy, sufficient preconception 25-hydroxyvitamin D, but not that at 8 weeks of gestation, was associated with reduced risk of pregnancy loss (preconception RR per 25 nmol/L 0·88 [95% CI 0·77-0·99]; 8 weeks of gestation 0·98 [0·95-1·01]). No association was observed with fecundability in women with sufficient versus those with insufficient preconception 25-hydroxyvitamin D concentrations (adjusted FOR 1·13 [95% CI 0·95-1·34]). INTERPRETATION: Sufficient preconception 25-hydroxyvitamin D (≥75 nmol/L) was associated with increased likelihood of pregnancy and livebirth. Increased vitamin D concentrations before conception, but not in early pregnancy, were associated with reduced pregnancy loss. FUNDING: National Institutes of Health and Doris Duke Charitable Foundation.

Pilot study of placental tissue collection, processing, and measurement procedures for large scale assessment of placental inflammation.

BACKGROUND: Placental dysfunction is related to many pregnancy complications, but collecting placental specimens for investigation in large scale epidemiologic studies is often infeasible. Standard procedures involving immediate collection after birth and snap freezing are often cost prohibitive. We aimed to collect pilot data regarding the feasibility and precision of a simpler approach, the collection of tissue samples following 24 hours of refrigeration of whole placentae at 4°C, as compared to the "gold standard" of snap freezing excised tissue within 40 minutes of delivery for the assessment of inflammatory cytokines. METHODS: Placentae were collected from 12 women after delivering live-born singleton babies via uncomplicated vaginal delivery. Two placentae were utilized to establish laboratory tissue processing and assay protocols. The other 10 placentae were utilized in a comparison of three tissue collection conditions. Specifically, key inflammatory cytokines were measured in 3 sections, representing three collection conditions. Sections 1 (full thickness) and 2 (excised prior to freezing) were obtained within 40 minutes of delivery and snap frozen in liquid nitrogen, and section 3 (full thickness) was obtained after refrigerating the placenta at 4°C for 24 hours. RESULTS: IL-6, IL-10, and IL-8 all had comparable concentrations and variability overall in all three section types. Levels of tumor necrosis factor alpha (TNF-α) were too low among samples to reliably measure using immunoassay. CONCLUSIONS: Refrigeration of placentae prior to processing does not appear to compromise detection of these cytokines for purposes of large scale studies. These findings provide a framework and preliminary data for the study of inflammatory cytokines within the placenta in large scale and/or resource-limited settings.

A prospective study of physical activity and fecundability in women with a history of pregnancy loss.

STUDY QUESTION: Is physical activity (PA) associated with fecundability in women with a history of prior pregnancy loss? SUMMARY ANSWER: Higher fecundability was related to walking among overweight/obese women and to vigorous PA in women overall. WHAT IS KNOWN ALREADY: PA may influence fecundability through altered endocrine function. Studies evaluating this association have primarily utilized Internet-based recruitment and self-report for pregnancy assessment and have yielded conflicting results. STUDY DESIGN, SIZE, DURATION: This is a secondary analysis of the Effects of Aspirin in Gestation and Reproduction (EAGeR) trial (2007-2011), a multisite, randomized controlled trial of preconception-initiated low-dose aspirin. PARTICIPANTS/MATERIALS, SETTING, METHODS: Healthy women (n = 1214), aged 18-40 and with 1-2 prior pregnancy losses, were recruited from four US medical centers. Participants were followed for up to six menstrual cycles while attempting pregnancy and through pregnancy for those who became pregnant. Time to hCG detected pregnancy was assessed using discrete-time Cox proportional hazard models to estimate fecundability odds ratios (FOR) adjusted for covariates, accounting for left truncation and right censoring. MAIN RESULTS AND THE ROLE OF CHANCE: The association of walking with fecundability varied significantly by BMI (P-interaction = 0.01). Among overweight/obese women, walking ≥10 min at a time was related to improved fecundability (FOR = 1.82, 95% CI: 1.19, 2.77). In adjusted models, women reporting >4 h/wk of vigorous activity had significantly higher fecundability (FOR = 1.69, 95% CI: 1.24, 2.31) compared to no vigorous activity. Associations of vigorous activity with fecundability were not significantly different by BMI (P-interaction = 0.9). Moderate activity, sitting, and International Physical Activity Questionnaire (IPAQ) categories were not associated with fecundability overall or in BMI-stratified analyses. LIMITATIONS, REASONS FOR CAUTION: Some misclassification of PA levels as determined by the short form of the IPAQ is likely to have occurred, and may have led to non-differential misclassification of exposure in our study. Information on diet and change in BMI was not collected and may have contributed to some residual confounding in our results. The generalizability of our results may be limited as our population consisted of women with a history of one or two pregnancy losses. WIDER IMPLICATIONS OF THE FINDINGS: These findings provide positive evidence for the benefits of PA in women attempting pregnancy, especially for walking among those with higher BMI. Further study is necessary to clarify possible mechanisms through which walking and vigorous activity might affect time-to-pregnancy. STUDY FUNDING/COMPETING INTEREST(S): This work was funded by the Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development. The authors report no conflicts of interest in this work. TRIAL REGISTRATION NUMBER: #NCT00467363.

Vitamin D is associated with bioavailability of androgens in eumenorrheic women with prior pregnancy loss.

BACKGROUND: Prior studies have reported mixed results regarding relationships between vitamin D, androgens, and sex hormone-binding globulin in patients with polycystic ovary syndrome. However, less is known regarding these associations in eumenorrheic, premenopausal women. OBJECTIVE: Our objective was to study the relationships between serum vitamin D and androgen biomarkers in eumenorrheic women with a history of pregnancy loss who were attempting pregnancy. STUDY DESIGN: This was an analysis of a cohort of 1191 participants from the Effects of Aspirin in Gestation and Reproduction trial (2006-2012). Participants were attempting to conceive, aged 18-40 years, with 1-2 documented prior pregnancy losses and no history of infertility, and recruited from 4 academic medical centers in the United States. Serum vitamin D (25-hydroxyvitamin D) and hormone concentrations were measured at baseline. RESULTS: Vitamin D concentration was negatively associated with free androgen index (percentage change [95% confidence interval, -5% (-8% to -2%)] per 10 ng/mL increase) and positively associated with sex hormone-binding globulin (95% confidence interval, 4% [2-7%]), although not with total testosterone, free testosterone, or dehydroepiandrosterone sulfate after adjusting for age, body mass index, smoking status, race, income, education, physical activity, and season of blood draw. CONCLUSION: Overall, vitamin D was associated with sex hormone-binding globulin and free androgen index in eumenorrheic women with prior pregnancy loss, suggesting that vitamin D may play a role in the bioavailability of androgens in eumenorrheic women. We are limited in making assessments regarding directionality, given the cross-sectional nature of our study.

Association of testosterone and antimüllerian hormone with time to pregnancy and pregnancy loss in fecund women attempting pregnancy.

OBJECTIVE: To examine whether higher T and/or antimüllerian hormone (AMH) was associated with anovulation, time to pregnancy (TTP), or pregnancy loss risk among healthy, fecund women without diagnosed polycystic ovary syndrome. DESIGN: Prospective cohort study conducted as a secondary analysis from the Effects of Aspirin in Gestation and Reproduction randomized trial. SETTING: University medical centers. PATIENT(S): A total of 1,198 healthy, eumenorrheic women aged 18-40 years attempting spontaneous pregnancy with one to two prior pregnancy losses were included. Women were categorized by baseline antimüllerian hormone (AMH), as a surrogate marker of antral follicle count, and T concentrations; the highest quartile for each was "high," and below the top quartile (i.e., lower 75% of values) was "norm," forming four groups: norm T/norm AMH (n = 742), norm T/high AMH (n = 156), high T/norm AMH (n = 157), and high T/high AMH (n = 143). INTERVENTION(S): Not applicable. MAIN OUTCOME MEASURE(S): Anovulation, pregnancy incidence, TTP, and pregnancy loss incidence. RESULT(S): Women with high T/high AMH had a greater anovulation risk (risk ratio 1.58, 95% confidence interval 1.13-2.22) compared with women with norm T/norm AMH, but with imprecise differences in incidence of pregnancy, TTP, or pregnancy loss. CONCLUSION(S): Women with higher T and AMH had more frequent anovulatory cycles but with marginal impacts on TTP or pregnancy loss. A continuum of mild inefficiency in reproductive function may be related to higher T and AMH, including in fecund women with normal menstrual cycles and no clinical diagnosis of polycystic ovary syndrome, but with unclear effects on fecundability and pregnancy loss. CLINICAL TRIAL REGISTRATION NUMBER: NCT00467363.

Prevalence and Contributors to Low-grade Inflammation in Three U.S. Populations of Reproductive Age Women.

BACKGROUND: Inflammation, measured by high-sensitivity C-reactive protein (hsCRP), is linked to adverse reproductive outcomes. However, prevalence and predictors of low-grade inflammation are poorly understood among reproductive age women. Therefore, the current aim was to characterize: (i) the prevalence of elevated hsCRP and (ii) whether the association of various demographic, anthropometric, life style, and metabolic characteristics with higher hsCRP varies across populations of reproductive age women with varying risk profiles for adverse reproductive outcomes. METHODS: Bivariate analysis of characteristics among women ages 18-40 having hsCRP <2.0 vs. ≥2.0 mg/L in the BioCycle Study (N = 259), the Effects of Aspirin in Gestation and Reproduction Trial (EAGeR) (N = 1228), and the National Health and Nutrition Examination Survey (NHANES; N = 2173) were conducted. Multivariable regression analysis estimated the association of all characteristics to hsCRP within each cohort. RESULTS: Prevalence of hsCRP≥2 mg/L ranged from 20 to 40%. Age, BMI, waist circumference, blood pressure, lipids, glucose, and insulin were frequently higher in women with hsCRP ≥2 mg/L. In multivariable models, however, only adiposity (BMI, waist circumference) was independently associated with hsCRP within all three cohorts. Some variables showed cohort-specific associations with higher hsCRP: white race (EAGeR), higher fasting glucose (BioCycle), and lesser education and employment (NHANES). The total characteristics explained 28-46% of the variation in hsCRP across the three cohorts. CONCLUSIONS: Low-grade inflammation was common, including among predominantly non-obese women, affecting from 20 to 40% of reproductive age women. Given the potential to reduce inflammation through inexpensive, widely available therapies, examination of the impact of chronic inflammation on reproductive and pregnancy outcomes, as well as preventive interventions, are now needed.