Maternal Biomarkers of Nutritional Status Prior to Pregnancy and Newborn Epigenetic Aging

Objectives

Maternal diet prior to and during pregnancy has been related to child health across the lifespan; however, mechanisms remain unclear. Gestational age acceleration (GAA), a measure of epigenetic aging relative to clinically estimated gestational age (GA), has emerged as a potential biomarker predictive of childhood BMI and atopic diseases. Few studies have evaluated the associations of maternal nutrient biomarkers, including methyl donors and fatty acids (FA), with GAA.

Methods

We evaluated associations among 391 mother-child dyads in the Effects of Aspirin in Gestation and Reproduction (EAGeR) trial. Women were randomized to low-dose aspirin (LDA) or placebo, both containing 400 μg folic acid, prior to and through 36 weeks pregnancy. Maternal folate, homocysteine, vitamin B-12, vitamin D, carotenoids, tocopherols, and plasma FAs were quantified from blood samples obtained ≤6 months prior to conception and at 8 weeks gestation. DNA methylation was measured with the Infinium MethylationEPIC BeadChip using cord blood DNA. Epigenetic GA was calculated using the Knight and Bohlin clocks. GAA was defined as the residual from a model regressing GA on epigenetic GA. We assessed associations between nutritional biomarkers and GAA using robust linear regression, controlling for maternal age, race, education, employment status, total cholesterol, and child sex. A false discovery rate (FDR) correction was applied to account for multiple comparisons using the Benjamini-Hochberg method.

Results

Mean (SD, range) clinically estimated GA at delivery was 38.9 (1.5, 31.1–44.9) weeks and was positively correlated with epigenetic age (Knight clock r = 0.51, Bohlin clock r = 0.76). Being female was positively related to GAAKnight. Maternal age was positively associated with GAABohlin. In multivariable regression models, preconception folate was inversely related to GAABohlin (β = −0.004, 95% CI: −0.007–0.000, P = 0.04); however, this was not significant after adjustment for multiple comparisons (FDR P = 0.82). Other nutritional biomarkers and LDA were not related to GAA.

Conclusions

Maternal nutritional biomarkers prior to conception and during early pregnancy were not related to newborn epigenetic age acceleration in predominantly term deliveries among women supplemented with folic acid.

Funding Sources

Supported by the Intramural Research Program of the NICHD.

Vitamin D and Reproductive Hormones Across the Menstrual Cycle

STUDY QUESTION

How do the calciotropic hormones (25-hydroxyvitamin D, 1,25-dihydroxyvitamin D and intact parathyroid hormone (iPTH)) vary across the menstrual cycle and do cyclic patterns of reproductive hormones (estradiol, progesterone, LH, FSH) differ by vitamin D status?

SUMMARY ANSWER

Calciotropic hormones vary minimally across the menstrual cycle; however, women with 25-hydroxyvitamin D below 30 ng/ml have lower mean estradiol across the menstrual cycle.

WHAT IS KNOWN ALREADY

Prior human studies suggest that vitamin D status is associated with fecundability, but the mechanism is unknown. Exogenous estrogens and prolonged changes in endogenous estradiol (pregnancy or menopause) influence concentrations of 25-hydroxyvitamin D. In vitro, treatment with 1,25-dihydroxyvitamin D increases steroidogenesis in ovarian granulosa cells. There are little data about changes in calciotropic hormones across the menstrual cycle or cyclic patterns of reproductive hormones by categories of vitamin D status.

STUDY DESIGN, SIZE, DURATION

A prospective cohort study of 89 self-identified white women aged 18-44, across two menstrual cycles. Participants were a subset of the BioCycle Study, a community-based study conducted at the University of Buffalo, 2005-2007.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Eligible participants had self-reported regular menstrual cycles between 21 and 35 days and were not using hormonal contraception or vitamins. Early morning fasting blood samples were drawn at up to eight study visits per cycle. Visits were timed to capture information in all cycle phases. Serum samples for 89 women (N = 163 menstrual cycles) were analyzed for estradiol, progesterone, LH, FSH and 25-hydroxyvitamin D (25(OH)D). Variability in calciotropic hormones within and across menstrual cycles was assessed using intraclass correlation coefficients and non-linear mixed models. Given the relative stability of the calciotropic hormones across the menstrual cycle, non-linear mixed models were used to examine differences in the cyclic patterns of estradiol, progesterone, LH and FSH by categories of each calciotropic hormone (split at the median). These models were conducted for all ovulatory cycles (N = 142 ovulatory menstrual cycles) and were adjusted for age, BMI (measured in clinic) and self-reported physical activity.

MAIN RESULTS AND THE ROLE OF CHANCE

Median 25(OH)D concentration was 29.5 ng/ml (SD 8.4), and only 6% of women had vitamin D deficiency (<20 ng/ml). The mean concentration of 25(OH)D did not differ between the luteal and follicular phase; however, both 1,25(OH)2D and iPTH showed small fluctuations across the menstrual cycle with the highest 1,25(OH)2D (and lowest iPTH) in the luteal phase. Compared with women who had mean 25(OH)D ≥30 ng/ml, women with lower 25(OH)D had 13.8% lower mean estradiol (95% confidence interval: -22.0, -4.7) and 10.8% lower free estradiol (95% CI: -0.07, -0.004). Additionally, compared to women with iPTH ≤36 pg/ml, women with higher concentrations of iPTH had 12.7% lower mean estradiol (95% CI: -18.7, -6.3) and 7.3% lower progesterone (95% CI: -13.3, -0.9). No differences in the cyclic pattern of any of the reproductive hormones were observed comparing cycles with higher and lower 1,25(OH)2D.

LIMITATIONS, REASONS FOR CAUTION

Women included in this study had self-reported 'regular' menstrual cycles and very few were found to have 25(OH)D deficiency. This limits our ability to examine cycle characteristics, anovulation and the effects of concentrations of the calciotropic hormones found in deficient individuals. Additionally, the results may not be generalizable to women with irregular cycles, other races, or populations with a higher prevalence of vitamin D deficiency.

WIDER IMPLICATIONS OF THE FINDINGS

These findings support current clinical practice that does not time testing for vitamin D deficiency to the menstrual cycle phase. We find that women with lower vitamin D status (lower 25(OH)D or higher iPTH) have lower mean concentrations of estradiol across the menstrual cycle. Although this study cannot identify a mechanism of action, further in vitro work or clinical trials may help elucidate the biologic mechanisms linking calciotropic and reproductive hormones.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the Intramural Research Programs of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health (contract numbers: HHSN275200403394C, HHSN275201100002I and Task 1 HHSN27500001) and the National Institute of Environmental Health Sciences. There are no competing interests.

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.

Preconception Blood Pressure and Its Change Into Early Pregnancy: Early Risk Factors for Preeclampsia and Gestational Hypertension

Preeclampsia and gestational hypertension are common complications of pregnancy associated with significant maternal and infant morbidity. Despite extensive research evaluating risk factors during pregnancy, most women who develop a hypertensive disorder of pregnancy are not considered high-risk and strategies for prevention remain elusive. We evaluated preconception blood pressure and its change into early pregnancy as novel risk markers for development of a hypertensive disorder of pregnancy. The EAGeR (Effects of Aspirin in Gestation and Reproduction) trial (2007-2011) randomized 1228 healthy women with a history of pregnancy loss to preconception-initiated low-dose aspirin versus placebo and followed participants for up to 6 menstrual cycles attempting pregnancy and throughout pregnancy if they became pregnant. Blood pressure was measured during preconception and throughout early gestation. The primary outcomes, preterm preeclampsia, term preeclampsia, and gestational hypertension, were abstracted from medical records. Among 586 women with a pregnancy >20 weeks' gestation, preconception blood pressure levels were higher for preterm preeclampsia (87.3±6.7 mm Hg mean arterial pressure), term preeclampsia (88.3±9.8 mm Hg), and gestational hypertension (87.9±9.1 mm Hg) as compared with no hypertensive disorder of pregnancy (83.9±8.6 mm Hg). Change in blood pressure from preconception into very early pregnancy was associated with development of preeclampsia (relative risk, 1.13 [95% CI, 1.02-1.25] per 2 mm Hg increase in mean arterial pressure at 4 weeks' gestation), particularly preterm preeclampsia (relative risk, 1.21 [95% CI, 1.01-1.45]). Randomization to aspirin did not alter blood pressure trajectory or risk of hypertension in pregnancy. Preconception blood pressure and longitudinal changes during early pregnancy are underexplored but crucial windows in the detection and prevention of hypertensive disorders of pregnancy. Registration- URL: http://www.clinicaltrials.gov. Unique identifier: NCT00467363.

Maternal Serum Lipid Trajectories and Association with Pregnancy Loss and Length of Gestation

OBJECTIVE

We characterized lipid trajectories and investigated lipids and rate of pregnancy lipid change with the risk of pregnancy loss or preterm delivery <37 weeks.

STUDY DESIGN

In a secondary analysis of 337 women with one to two prior losses assigned to placebo in a randomized controlled trial at four centers (2007-2012), cholesterol, low- and high-density lipoprotein cholesterol (HDL-C), and triglycerides were measured up to 6 months prepregnancy (time 0) and pregnancy up to 7 visits. Trajectories were created using linear mixed models. Multivariable logistic regression with adjustment for maternal characteristics and cholesterol was performed.

RESULTS

Lipids decreased from prepregnancy to 4 to 5 weeks, followed by an increase, and were biphasic or triphasic depending on the lipid component. Between 4 and 8 weeks, for every 1-unit increase in HDL-C, there was a 22% decreased odds of loss <14 weeks (odds ratio: 0.78; 95% confidence interval: 0.60, 0.99) and 24% decreased odds of loss or preterm delivery 14 to <37 weeks (odds ratio: 0.76; 95% confidence interval: 0.60, 0.96).

CONCLUSION

There were no associations with other lipid components or other time points. An impaired rise of HDL-C early in pregnancy may signal maladaptation to pregnancy that is associated with pregnancy loss or preterm delivery.

Maternal preconception lipid profile and gestational lipid changes in relation to birthweight outcomes

In 575 women with 1–2 prior pregnancy losses; total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides (TG) were evaluated preconception and throughout pregnancy to evaluate whether previously observed associations between third trimester maternal lipid profile and birthweight outcomes are driven by preconception lipids or lipid changes during pregnancy. Lipid trajectories were compared by pre-pregnancy body mass index (BMI) <25 or ≥25 kg/m²; logistic regression models evaluated preconception lipid concentration and change from preconception to 28 weeks with adjusted odds of large- or small-for-gestational age (LGA or SGA) neonate by BMI group. Preconception lipid concentrations and gestational lipid trajectories varied by BMI group (P < 0.001). Preconception lipids were not associated with LGA or SGA in either group. A 10 mg/dL increase in HDL-C change from preconception to 28 weeks was associated with decreased odds of LGA (odds ratio (OR) = 0.63, 95% confidence interval (CI): 0.46, 0.86) and 10 mg/dL increase in TG change associated with increased odds of LGA (OR = 1.05, 95% CI: 1.01, 1.1) overall. For ≥25 BMI only, 10 mg/dL increase in HDL-C change was associated with decreased SGA odds (OR = 0.35, 95% CI: 0.19, 0.64). Gestational lipid trajectories differed by BMI group and were differentially associated with birthweight outcomes, with HDL-C more strongly associated with healthy birthweight in women with BMI ≥25.

Preconception Marijuana Use and Pregnancy Outcomes (P18-033-19)

Objectives

Marijuana is the most widely used and fastest growing drug in the United States, with legislation currently broadening legalization for both medical and recreational use. However, there are limited data evaluating associations with fecundity and adverse pregnancy outcomes. A few studies evaluating self-reported use suggest marijuana may not be harmful for pregnancy, yet there is a concern for underreporting due to stigma as marijuana is not universally legalized. Our aim was to examine the association between preconception marijuana use, using both self-reported and urinary levels of tetrahydrocannabinol (THC), and fecundability, live birth, and pregnancy loss.

Methods

Women aged 18–40 years old (n = 1212) enrolled in the EAGeR trial were screened for urinary THC at up to 2 time points during preconception using a homogenous enzyme immunoassay from Randox Laboratories, and asked at baseline to report any marijuana use during the past year. Women were followed for up to 6 months while attempting pregnancy. Cox proportional hazard regression was used to calculate fecundability odds ratios (FOR), and log-binomial regression to estimate risk ratios (RR) for live birth and pregnancy loss adjusting for age, race, BMI, education, smoking, alcohol, and detectable levels of opioids.

Results

33 (2.7%) women screened positive for THC during the preconception period, of which 14 also self-reported use during the past year. 62 women (5.1%) either screened positive or self-reported use. Women who screened positive for preconception THC had reduced fecundability (FOR 0.50; 95% CI 0.25, 1.00), as well as women who self-reported marijuana use (FOR 0.54; 95% CI 0.31, 0.94), or who were positive using either urinary or self-report (FOR 0.53, 95% CI 0.33, 0.86). No associations were observed between marijuana use and live birth (RR 0.71; 95% CI 0.41, 1.22) and pregnancy loss (RR 0.78; 95% CI 0.28, 2.18).

Conclusions

Women who screened positive for THC during preconception, or self-reported use during the past year had reduced fecundability, though no associations were observed with live birth or pregnancy loss. Further investigations are needed to determine what duration and dose of marijuana may negatively impact fecundability.

Funding Sources

Intramural Research Program, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development.

Preconception Vitamin D Status and Offspring Sex Ratio Among Women with Prior Pregnancy Loss (OR17-05-19)

Objectives

Experimental data indicate that maternal exposure to factors known to alter inflammatory milieu may be specifically harmful to the conception or survival of male fetuses. Indeed, in a recent clinical trial, preconception administration of low dose aspirin versus placebo restored the skewed sex ratio at birth among women with elevated inflammation, providing direct evidence of this phenomenon in humans. However, it is unknown whether other factors associated with inflammation, such as vitamin D status, are associated with offspring sex ratio at birth. Our objective was thus to evaluate the association of preconception serum 25-hydroxyvitamin D levels [25(OH)D] and male live birth among 1228 reproductive-age women with a history of 1–2 prior losses who were enrolled in the Effects of Aspirin in Gestation and Reproduction trial between 2007–2011.

Methods

We estimated RRs and 95% CIs for male live birth according to 25(OH)D sufficiency (≥75 vs. <75 nmol/L) using generalized estimating equations of log-binomial regression with robust standard errors.

Results

Among the 1086 women who completed follow-up, the proportion of live-born males was 24% (n = 136) and 30% (n = 156) in the 25(OH)D insufficient and sufficient groups, respectively. After adjustment for age, race/ethnicity, and other factors, women in the 25(OH)D sufficient group were 23% (95% CI: 1.01, 1.49) more likely to have a live-born male infant compared to the insufficient group. Associations were stronger among women with elevated versus low levels of high sensitivity C-reactive protein (>1.95 ng/mL: RR: 1.41; 95% CI: 0.99, 2.00 versus ≤1.95 ng/mL RR: 1.11; 95% CI: 0.88, 1.41), a marker of systemic low-grade inflammation.

Conclusions

Preconception vitamin D status was associated with male live birth, particularly among women with low-grade inflammation. These data suggest that maternal vitamin D sufficiency may mitigate maternal inflammation that would otherwise be detrimental to male fetal survival.

Funding Sources

Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD.

Vitamin D and Premenstrual Syndrome in Healthy Women with Regular Cycles (P18-056-19)

Objectives

Vitamin D levels have been associated with premenstrual syndrome (PMS) and symptom severity, but data are mixed. Our aim was to assess the relationship between serum vitamin D and PMS in women with regular menstrual cycles.

Methods

We looked at vitamin D and PMS using two cohorts of healthy women with regular cycles. BioCycle followed 76 women, for up to 2 menstrual cycles prospectively and EAGeR followed 1191 women with 1–2 prior pregnancy losses. 25(OH)D was measured in serum at baseline in both cohorts, with PMS assessed via questionnaire evaluating the presence and severity of 14 psychological and physical menstrual symptoms the week before and after menses. EAGeR assessed symptoms over the past year, and BioCycle assessed symptoms prospectively over the next cycle. We used status and PMS associations adjusting for age, BMI, race, smoking, income, physical activity, and season of blood draw.

Results

54% and 47% of women had sufficient 25(OH)D (≥30 ng/mL) and 33% and 40% exhibited PMS in BioCycle and EAGeR, respectively. Vitamin D status was not associated with risk of PMS in either cohort (BioCycle: D insufficiency was associated with risk of breast fullness/tenderness (RR 1.27, 95% CI 1.03, 1.55) and generalized aches and pains (RR 1.33, 95% CI 1.01, 1.78), compared to women with vitamin D sufficiency. Similar associations were observed in BioCycle though confidence intervals were wide. No associations were observed between vitamin D status and psychological symptoms.

Conclusions

Among women with regular menses, 25(OH)D was not associated with PMS, though it may be associated with individual symptoms. Additional studies are needed to understand these relationships in women with irregular menstrual.

Funding Sources

Intramural Research Program, Division of Population Health Research, NICHD. NIH Medical Research Scholars Program. Doris Duke Charitable Foundation.

Caffeinated Beverage Intake and Serum Caffeine Metabolites and Risk of Pregnancy Loss (OR17-04-19)

Objectives

The association between caffeine and pregnancy loss remains controversial due to limitations of prior studies such as relying on self-reported intake only, exposure measurement after clinical confirmation of pregnancy, and potential time-varying confounding by nausea/vomiting and lifestyle factors, which may be affected by prior caffeine exposure. Thus, our aim was to evaluate associations of preconception and early pregnancy serum caffeine, paraxanthine, and theobromine, self-reported intake of caffeinated beverages, and risk of pregnancy loss among 1228 reproductive-age women attempting pregnancy in the EAGeR trial during 2007–2011.

Methods

We estimated HRs and 95% CIs for any pregnancy loss, hCG loss (prior to ultrasound confirmation), and clinical loss (after ultrasound confirmation) according to caffeinated beverage intake and caffeine biomarkers measured at preconception and the 8th week of gestation using weighted adjusted Cox proportional hazards models.

Results

At preconception, 67%, 28%, and 9% of women reported any intake of caffeinated sodas, coffee, and tea, respectively. Preconception total caffeinated beverage intake of ≥3 vs. 0 cups/day was associated with 85% (95% CI: 1.18, 2.94) higher risk of any pregnancy loss, driven primarily by associations for hCG loss (HR: 2.88 (95% CI: 1.20, 6.91)). Caffeinated soda intake was associated with hCG loss (≥2 vs. <2 cups/day HR: 2.11 (95% CI: 1.14, 3.89)), whereas caffeinated coffee intake was associated with clinical loss (≥2 vs. <2 cups/day HR: 1.27 (95% CI: 1.02, 2.90)). Likewise, any detectable level of serum caffeine (>0.2 vs. ≤0.2 ng/mL) at preconception was strongly associated with hCG loss (HR: 4.51 (95% CI: 1.36, 14.91)). Serum caffeine, paraxanthine, and theobromine measured at the 8th week of gestation were not associated with risk of loss.

Conclusions

Collectively, these data suggest that caffeine intake prior to pregnancy may increase risk of pregnancy loss, particularly in early gestation.

Funding Sources

Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD.

Preconception Blood Pressure Levels and Reproductive Outcomes in a Prospective Cohort of Women Attempting Pregnancy

Elevated blood pressure in young adulthood is an early risk marker for cardiovascular disease. Despite a strong biological rationale, little research has evaluated whether incremental increases in preconception blood pressure have early consequences for reproductive health. We evaluated preconception blood pressure and fecundability, pregnancy loss, and live birth in the EAGeR trial (Effects of Aspirin on Gestational and Reproduction; 2007-2011), a randomized clinical trial of aspirin and reproductive outcomes among 1228 women attempting pregnancy with a history of pregnancy loss. Systolic and diastolic blood pressure were measured during preconception in the first observed menstrual cycle and in early pregnancy and used to derive mean arterial pressure. Fecundability was assessed as number of menstrual cycles until pregnancy, determined through human chorionic gonadotropin testing. Pregnancy loss included both human chorionic gonadotropin-detected and clinical losses. Analyses adjusted for treatment assignment, age, body mass index, race, marital status, smoking, parity, and time since last loss. Mean preconception systolic and diastolic blood pressure were 111.6 mm Hg (SD, 12.1) and 72.5 (SD, 9.4) mm Hg. Risk of pregnancy loss increased 18% per 10 mm Hg increase in diastolic blood pressure (95% confidence interval, 1.03-1.36) and 17% per 10 mm Hg increase in mean arterial pressure (95% confidence interval, 1.02-1.35) in adjusted analyses. Findings were similar for early pregnancy blood pressure. Preconception blood pressure was not related to fecundability or live birth in adjusted analyses. Findings suggest that preconception blood pressure among healthy women is associated with pregnancy loss, and lifestyle interventions targeting blood pressure among young women may favorably impact reproductive health.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00467363.

Blood lead, cadmium and mercury in relation to homocysteine and C-reactive protein in women of reproductive age: a panel study

BACKGROUND

To examine the relationship between cadmium, lead, and mercury concentrations with high-sensitivity C-reactive protein (hs-CRP) and homocysteine in women.

METHODS

Metals were measured at enrollment in whole blood. Homocysteine and hs-CRP were measured in one (N = 9) or two (N = 250) menstrual cycles up to 3 and 8 times per cycle, respectively. Linear mixed models with inverse probability of exposure weights to account for time varying confounding were used and models were stratified by dietary and serum vitamin status (dietary: vitamin B₆, B₁₂, folate; serum: folate).

RESULTS

Geometric mean (95% confidence interval (CI)) concentrations for cadmium, lead, and mercury were 0.29 (0.26-0.31) μg/L, 0.91 (0.86-0.96) μg/dL, and 1.05 (0.93-1.18) μg/L, respectively. Lead was associated with increased homocysteine (0.08; 95% CI: 0.01, 0.15) and this persisted among those in the lower three quartiles of consumption of vitamin B₆, B₁₂, folate, and serum folate but was not significant among those in the upper quartile. No associations were observed between metals and hs-CRP.

CONCLUSIONS

Blood lead was associated with increased homocysteine in a cohort of healthy, premenopausal women but these associations did not persist among those consuming ≥75th percentile of essential micronutrients. Cadmium, lead, and mercury were not associated with hs-CRP concentrations.

Preconception maternal lipoprotein levels in relation to fecundability

STUDY QUESTION

Are maternal preconception lipid levels associated with fecundability?

SUMMARY ANSWER

Fecundability was reduced for all abnormal female lipid levels including total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and total triglyceride levels.

WHAT IS KNOWN ALREADY

Subfecundity affects 7-15% of the population and lipid disorders are hypothesized to play a role since cholesterol acts as a substrate for the synthesis of steroid hormones. Evidence illustrating this relationship at the mechanistic level is mounting but few studies in humans have explored the role of preconception lipids in fecundity.

STUDY DESIGN, SIZE, DURATION

A secondary analysis of the Effects of Aspirin in Gestation and Reproduction (EAGeR) trial (2007-2011), a block-randomized, double-blind, placebo-controlled trial.

PARTICIPANTS/MATERIALS, SETTING, METHODS

A total of 1228 women, with 1-2 prior pregnancy losses and without a diagnosis of infertility, attempting pregnancy for up to six menstrual cycles were recruited from clinical sites in Utah, New York, PA and Colorado. Time to pregnancy was the number of menstrual cycles to pregnancy as determined by positive hCG test or ultrasound. Individual preconception lipoproteins were measured at baseline, prior to treatment randomization and dichotomized based on clinically accepted cut-points as total cholesterol ≥200 mg/dl, LDL-C ≥130 mg/dl, HDL-C <50 mg/dl and triglycerides ≥150 mg/dl.

MAIN RESULTS AND THE ROLE OF CHANCE

There were 148 (12.3%) women with elevated total cholesterol, 94 (7.9%) with elevated LDL-C, 280 (23.2%) with elevated triglycerides and 606 (50.7%) with low HDL-C. The fecundability odds ratio (FOR) was reduced for all abnormal lipids before and after confounder adjustment, indicating reduced fecundability. Total cholesterol ≥200 mg/dl was associated with 24% (FOR: 0.76, 95% CI: 0.59, 0.97) and 29% (FOR: 0.71, 95% CI: 0.55, 0.93) reduced fecundability for hCG-detected and ultrasound-confirmed pregnancy, respectively, compared with total cholesterol <200 mg/dl. There was a 19-36% decrease in the probability of conception per cycle for women with abnormal lipoprotein levels, though additional adjustment for central adiposity and BMI attenuated observed associations.

LIMITATIONS, REASONS FOR CAUTION

Although the FOR is a measure of couple fecundability, we had only measures of female lipid levels and can therefore not confirm the findings from a previous study indicating the independent role of male lipids in fecundity. The attenuated estimates and decreased precision after adjustment for central adiposity and obesity indicate the complexity of potential causal lipid pathways, suggesting other factors related to obesity besides dyslipidemia likely contribute to reduced fecundability.

WIDER IMPLICATIONS OF THE FINDINGS

Our results are consistent with one other study relating preconception lipid concentrations to fecundity and expand these findings by adding critically important information about individual lipoproteins. As lipid levels are modifiable they may offer an inexpensive target to improve female fecundability.

STUDY FUNDING AND COMPETING INTEREST(S)

This study was funded by the Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development. The authors have declared that no conflicts of interest exist.

TRIAL REGISTRATION NUMBER

#NCT00467363.

Variability and exposure classification of urinary phenol and paraben metabolite concentrations in reproductive-aged women

BACKGROUND

Human exposure to phenols and parabens is widespread. Within-person variability of urinary concentrations in healthy women is not well characterized.

OBJECTIVES

To characterize the variability of urinary phenol and paraben concentrations across two months and evaluate the ability of a single spot urine sample to characterize exposure.

METHODS

143 women provided 509 spot urine samples collected across two months of study (3-5 samples/woman). We measured urinary concentrations of 8 phenols: bisphenol A (BPA), benzophenone-3 (BP-3), benzophenone-1 (BP-1), 2,4-dichlorophenol (2,4-DCP), 2,5-dichlorophenol (2,5-DCP), 2,4,5-trichlorophenol (2,4,5-TCP), 2,4,6-trichlorophenol (2,4,6-TCP), triclosan (TCS); and 8 parabens and their metabolites (benzyl (BzP), butyl (BuP), ethyl (EtP), heptyl (HeP), methyl (MeP), propyl (PrP), 4-hydroxybenzoic acid (4-HB), 3,4-dihydroxybenzoic acid (3,4-DHB)). Biomarker variability was characterized using the intraclass correlation coefficient (ICC) and surrogate category analyses were conducted.

RESULTS

ICCs ranged from very low for BPA (0.04) to moderate for BP-3, BP-1, TCS, BzP, and MeP (0.66, 0.58, 0.55, 0.54, and 0.62, respectively). Surrogate analyses suggested that BP-1, BP-3, TCS, 2,4-DCP, BuP, and PrP may be characterized by a single spot sample (sensitivity range 0.76-0.86) but that additional samples were necessary for BPA, HeP, 4-HB, and 3,4-DHB (sensitivity range 0.47-0.61).

CONCLUSIONS

Urinary phenol and paraben metabolite concentrations were variable across two months in healthy women but the degree of reliability differed by the specific biomarker. A small number of samples may sufficiently characterize typical concentrations for BP-3, BP-1, TCS, BuP, and PrP; but additional biospecimens may be necessary to characterize exposure for other compounds, including BPA.

Low-dose aspirin and preterm birth: a randomized controlled trial

OBJECTIVE

To evaluate the association between low-dose aspirin initiated before conception and the risk of preterm birth.

METHODS

This was a secondary analysis of the Effects of Aspirin in Gestation and Reproduction trial. Women with a history of pregnancy loss (original stratum: one loss less than 20 weeks of gestation during the previous year; expanded stratum: one or two losses with no restrictions on timing or gestational age of the losses) were randomized to either daily low-dose aspirin (81 mg, n=615) and folic acid or folic acid alone (placebo; n=613). Preterm birth was compared between groups using intent-to-treat analysis.

RESULTS

Preterm birth rates were 4.1% (22/535 low-dose aspirin) and 5.7% (31/543 placebo) (relative risk [RR] 0.72, 95% confidence interval [CI] 0.42-1.23); spontaneous preterm birth rates were 1.1% (6/535 low-dose aspirin) and 2.2% (12/543 placebo) (RR 0.51, 95% CI 0.19-1.34); medically indicated preterm birth rates were 2.6% (14/535 low-dose aspirin) and 2.9% (16/543 placebo) (RR 0.89, 95% CI 0.44-1.80). After restriction to confirmed pregnancies using inverse probability weighting, preterm birth rates were 5.7% and 9.0% (RR 0.63, 95% CI 0.37-1.09) and spontaneous preterm birth rates were 1.4% and 3.2% (RR 0.44, 95% CI 0.17-1.18). In confirmed pregnancies in the original stratum, preterm birth occurred in 3.8% and 9.7% of the low-dose aspirin and placebo groups, respectively (RR 0.39, 95% CI 0.16-0.94).

CONCLUSION

Preconception low-dose aspirin was not significantly associated with the overall rate of preterm birth. Although the study was underpowered for this secondary analysis, numeric trends in favor of benefit, particularly in the women with a recent, single early pregnancy loss, warrant further investigation.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, www.clinicaltrials.gov, NCT00467363.

Neonatal outcomes in early term birth

OBJECTIVE

To determine neonatal morbidity rates for early term birth compared with full term birth by precursor leading to delivery.

STUDY DESIGN

This was a retrospective study of 188,809 deliveries from 37 0/7 to 41 6/7 weeks of gestation with electronic medical record data from 2002 to 2008. Precursors for delivery were categorized as spontaneous labor, premature rupture of membranes indicated, and no recorded indication. After excluding anomalies, rates of neonatal morbidities by precursor were compared at each week of delivery.

RESULTS

Early term births (37 0/7-38 6/7 weeks) accounted for 34.1% of term births. Overall, 53.6% of early term births were due to spontaneous labor, followed by 27.6% indicated, 15.5% with no recorded indication, and 3.3% with premature rupture of membranes. Neonatal intensive care unit admission and respiratory morbidity were lowest at or beyond 39 weeks compared with the early term period for most precursors, although indicated deliveries had the highest morbidity compared with other precursors. The greatest difference in morbidity was between 37 and 39 weeks for most precursors, although most differences in morbidities between 38 and 39 weeks were not significant. Respiratory morbidity was higher at 37 than 39 weeks regardless of route of delivery.

CONCLUSION

Given the higher neonatal morbidity at 37 compared with 39 weeks regardless of delivery precursor, our data support recent recommendations for designating early term to include 37 weeks. Prospective data is urgently needed to determine the optimal timing of delivery for common pregnancy complications.

Biological variability in serum anti-Müllerian hormone throughout the menstrual cycle in ovulatory and sporadic anovulatory cycles in eumenorrheic women

STUDY QUESTION

Does serum anti-Müllerian hormone (AMH) vary significantly throughout both ovulatory and sporadic anovulatory menstrual cycles in healthy premenopausal women?

SUMMARY ANSWER

Serum AMH levels vary statistically significantly across the menstrual cycle in both ovulatory and sporadic anovulatory cycles of healthy eumenorrheic women.

WHAT IS KNOWN ALREADY

Studies to date evaluating serum AMH levels throughout the menstrual cycle have conflicting results regarding intra-woman cyclicity. No previous studies have evaluated an association between AMH and sporadic anovulation.

STUDY DESIGN, SIZE, DURATION

We conducted a prospective cohort study of 259 regularly menstruating women recruited between 2005 and 2007.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Women aged 18-44 years were followed for one (n = 9) or two (n = 250) menstrual cycles. Anovulatory cycles were defined as any cycle with peak progesterone concentration ≤5 ng/ml and no serum LH peak on the mid or late luteal visits. Serum AMH was measured at up to eight-time points throughout each cycle.

MAIN RESULTS AND THE ROLE OF CHANCE

Geometric mean AMH levels were observed to vary across the menstrual cycle (P < 0.01) with the highest levels observed during the mid-follicular phase at 2.06 ng/ml, decreasing around the time of ovulation to 1.79 ng/ml and increasing thereafter to 1.93 (mid-follicular versus ovulation, P < 0.01; ovulation versus late luteal, P = 0.01; mid-follicular versus late luteal, P = 0.05). Patterns were similar across all age groups and during ovulatory and anovulatory cycles, with higher levels of AMH observed among women with one or more anovulatory cycles (P = 0.03).

LIMITATIONS, REASONS FOR CAUTION

Ovulatory status was not verified by direct visualization. AMH was analyzed using the original Generation II enzymatically amplified two-site immunoassay, which has been shown to be susceptible to assay interference. Thus, absolute levels should be interpreted with caution, however, patterns and associations remain consistent and any potential bias would be non-differential.

WIDER IMPLICATIONS OF THE FINDINGS

This study demonstrates a significant variation in serum AMH levels across the menstrual cycle regardless of ovulatory status. This variability, although statistically significant, is not large enough to warrant a change in current clinical practice to time AMH measurements to cycle day/phase.

STUDY FUNDING/COMPETING INTERESTS

This research was supported by the Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, MD (Contracts # HHSN275200403394C, HHSN275201100002I Task 1 HHSN27500001). The authors have no conflicts of interest to declare.

Association of cadmium, lead and mercury with paraoxonase 1 activity in women

BACKGROUND

The activity of paraoxonase 1 (PON1), an antioxidant enzyme whose polymorphisms have been associated with cancer risk, may be associated with metals exposure.

OBJECTIVE

To evaluate PON1 activity in relation to cadmium, lead, and mercury levels in healthy, premenopausal women.

METHODS

Women from upstate New York were followed for ≥ two menstrual cycles. Repeated measures linear mixed models estimated the association between cadmium, lead, and mercury levels (by tertile: T1, T2, T3) and PON1 arylesterase (PON1A) and PON1 paraoxonase (PON1P) activity, separately. Analyses were stratified by PON1 Q192R phenotype and un-stratified.

RESULTS

Median blood cadmium, lead, and mercury concentrations were 0.30 µg/L, 0.87 µg/dL, and 1.15 µg/L. In un-stratified analyses cadmium and mercury were associated with decreased PON1A activity (T2 vs. T1; not T3 vs. T1) but metals were not associated with PON1P. Phenotypes were distributed between QQ (n = 99), QR (n = 117), and RR (n = 34). Cadmium was associated with decreased PON1A activity for QR and RR phenotypes comparing T2 vs. T1 (-14.4% 95% confidence interval [CI] [-20.1, -8.4] and -27.9% [-39.5, -14.0],). Lead was associated with decreased PON1A (RR phenotype, T3 vs. T1 -18.9% [-32.5, -2.5]; T2 vs. T1 -19.6% [-32.4, -4.4]). Cadmium was associated with lower PON1P comparing T2 vs. T1 for the RR (-34.9% [-51.5, -12.5]) and QR phenotypes (-9.5% [-18.1, 0.0]) but not comparing T3 vs. T1. Cadmium was associated with increases in PON1P levels (QQ phenotype, T3 vs. T1 24.5% [7.0, 44.9]) and mercury was associated with increased PON1A levels (QQ phenotype, T3 vs. T1 6.2% [0.2, 12.6]). Mercury was associated with decreased PON1P (RR phenotype, T2 vs. T1 -22.8 [-37.8, -4.1]).

CONCLUSION

Blood metals were associated with PON1 activity and these effects varied by phenotype. However, there was not a linear dose-response and these findings await replication.

Measuring β-cell function relative to insulin sensitivity in youth: does the hyperglycemic clamp suffice?

OBJECTIVE

To compare β-cell function relative to insulin sensitivity, disposition index (DI), calculated from two clamps (2cDI, insulin sensitivity from the hyperinsulinemic-euglycemic clamp and first-phase insulin from the hyperglycemic clamp) with the DI calculated from the hyperglycemic clamp alone (hcDI).

RESEARCH DESIGN AND METHODS

Complete data from hyperglycemic and hyperinsulinemic-euglycemic clamps were available for 330 youth: 73 normal weight, 168 obese with normal glucose tolerance, 57 obese with impaired glucose tolerance, and 32 obese with type 2 diabetes. The correlation between hcDI and 2cDI and Bland-Altman analysis of agreement between the two were examined.

RESULTS

Insulin sensitivity and first-phase insulin from hcDI showed a hyperbolic relationship. The hcDI correlated significantly with 2cDI in the groups combined (r = 0.85, P < 0.001) and within each group separately (r ≥ 62, P < 0.001). Similar to 2cDI, hcDI showed a declining pattern of β-cell function across the glucose-tolerance groups. Overall, hcDI values were 27% greater than 2cDI, due to the hyperglycemic versus euglycemic conditions, reflected in a positive bias with Bland-Altman analysis.

CONCLUSIONS

β-Cell function relative to insulin sensitivity could be accurately evaluated from a single hyperglycemic clamp, obviating the need for two separate clamp experiments, when lessening participant burden and reducing research costs are important considerations.