What is the association between perceived stress during peri-conception and early pregnancy and pregnancy loss among women who have experienced a prior pregnancy loss? Daily perceived stress above the median is associated with over a 2-fold risk of early pregnancy loss among women who have experienced a prior loss. WHAT IS KNOWN ALREADY? Women who have experienced a pregnancy loss may be more vulnerable to stress while trying to become pregnant again. While prior research has indicated a link between psychological stress and clinically confirmed miscarriages, research is lacking among a pre-conceptional cohort followed prospectively for the effects of perceived stress during early critical windows of pregnancy establishment on risk of both hCG-detected pregnancy losses and confirmed losses, while considering important time-varying confounders. STUDY DESIGN, SIZE, Secondary data analysis of the EAGeR trial (2007-2011) among women with an hCG-detected pregnancy (n = 797 women). PARTICIPANTS/MATERIALS, SETTING, Women from four US clinical centers enrolled pre-conceptionally and were followed ≤6 cycles while attempting pregnancy and, as applicable, throughout pregnancy. Perceived stress was captured via daily diaries and end-of-month questionnaires. Main outcome measures include hCG-detected and clinically recognized pregnancy losses. MAIN Among women who had an hCG-confirmed pregnancy, 188 pregnancies (23.6%) ended in loss. Women with high (>50th percentile) versus low (≤50th percentile) peri-implantation or early pregnancy weekly perceived stress had an elevated risk of experiencing any pregnancy loss (hazard ratio (HR): 1.69, 95% CI: 1.13, 2.54) or clinical loss (HR: 1.58, 95% CI: 0.96, 2.60), with higher risks observed for women experiencing an hCG-detected loss (HR: 2.16, 95% CI: 1.04, 4.46). Models accounted for women's age, BMI, employment, marital status, income, education, race, parity, prior losses, exercise and time-varying nausea/vomiting, caffeine, alcohol and smoking. LIMITATIONS, We were limited in our ability to clearly identify the mechanisms of stress on pregnancy loss due to our sole reliance on self-reported perceived stress, and the lack of biomarkers of different pathways of stress. This study provides new insight on early pregnancy perceived stress and risk of pregnancy loss, most notably hCG-detected losses, among women with a history of a prior loss. Our study is an improvement over past studies in its ability to account for time-varying early pregnancy symptoms, such as nausea/vomiting, and lifestyle factors, such as caffeine, alcohol and smoking, which are also risk factors for psychological stress and pregnancy loss. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by the Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland (Contract numbers: HHSN267200603423, HHSN267200603424, HHSN267200603426, HHSN275201300023I). Additionally, K.C.S. was supported by the National Institute on Aging of the National Institutes of Health under Award Number K01AG058781. The authors have no conflicts of interest to disclose. #NCT00467363.
Purdue-Smithe AC et al., 2022·Am J Clin Nutr·
Open Access
Caffeine is the most frequently used psychoactive substance in the United States and >90% of reproductive-age women report some amount of intake daily. Despite biological plausibility, previous studies on caffeine and fecundability report conflicting results. Importantly, prior studies measured caffeine exposure exclusively by self-report, which is subject to measurement error and does not account for factors that influence caffeine metabolism. Our objective was to examine associations between preconception serum caffeine metabolites, caffeinated beverage intake, and fecundability. Participants included 1228 women aged 18-40 y with a history of 1-2 pregnancy losses in the EAGeR (Effects of Aspirin in Gestation and Reproduction) trial. We prospectively evaluated associations of preconception caffeine metabolites (i.e., caffeine, paraxanthine, and theobromine) measured from 1191 serum samples untimed to a specific time of day, self-reported usual caffeinated beverage intakes at baseline, and time-varying cycle-average caffeinated beverage intake, with fecundability. Using Cox proportional hazards models, we estimated fecundability odds ratios (FORs) and 95% CIs according to each metabolite. Follow-up was complete for 89% (n = 1088) of participants. At baseline, 85%, 73%, and 91% of women had detectable serum caffeine, paraxanthine, and theobromine, respectively. A total of 797 women became pregnant during ≤6 cycles of preconception follow-up. After adjusting for potential confounders, neither serum caffeine [tertile (T)3 compared with T1 For: 0.87; 95% CI: 0.71, 1.08], paraxanthine (T3 compared with T1 For: 0.92; 95% CI: 0.75, 1.14), nor theobromine (T3 compared with T1 For: 1.15; 95% CI: 0.95, 1.40) were associated with fecundability. Baseline intake of total caffeinated beverages was not associated with fecundability (>3 compared with 0 servings/d adjusted For: 0.99; 95% CI: 0.74, 1.34), nor was caffeinated coffee (>2 compared with 0 servings/d adjusted For: 0.93; 95% CI: 0.45, 1.92) or caffeinated soda (>2 servings/d adjusted For: 0.92; 95% CI: 0.71, 1.20). Our findings are reassuring that caffeine exposure from usual low to moderate caffeinated beverage intake likely does not influence fecundability.This trial was registered at clinicaltrials.gov as NCT00467363.
DeVilbiss EA et al., 2020·Paediatr Perinat Epidemiol·
Attaining pregnancy is conditional upon a series of complex processes, including adequately timed intercourse, ovulation, fertilisation, and implantation. Anovulation is a first-line treatment target for couples with difficulty conceiving and is frequently examined in studies of fecundability. To identify whether sporadic anovulation is an important determinant of cumulative pregnancy rates and time to pregnancy among fertile women with regular menstrual cycles. We simulated cumulative pregnancy rates and time to pregnancy for 12 consecutive menstrual cycles among 100 000 women based on data-driven probabilities of implantation, fertilisation, ovulation, and intercourse occurring in the fertile window. We assumed anovulation probabilities of 1%, 8%, or 14.5% and intercourse averaging once per week, every other day, or daily. The model incorporated reductions in implantation and fertilisation rates for successive cycles of non-pregnancy. After 12 cycles, a reduction in the per cycle incidence of anovulation from 14.5% to 1% resulted in a 4.0% higher cumulative pregnancy rate (86.7% vs 90.7%) and similar time to pregnancy (1-cycle median difference). In contrast, increasing mean unscheduled sexual intercourse frequency from weekly to every other day was associated with a 5-cycle median reduction in time to pregnancy (weekly: 7 cycles; every other day or daily: 2 cycles) and a 28.9% increase in the cumulative pregnancy rate (weekly: 59.9%, every other day: 88.8%; daily: 91.6%). In presumed fertile women with regular menstrual cycles, routine investigation of anovulation may not be an informative outcome in studies of fecundability, and routine testing to ensure ovulation and treatment of anovulation are unlikely to be medically necessary. While biomarkers or cervical fluid may help time intercourse to the fertile window, time to pregnancy can also be improved through increasing the frequency of unscheduled intercourse. These findings need corroboration in large preconception time to pregnancy studies.
Michels KA et al., 2020·Chronobiol Int·
Open Access
Despite research indicating that sleep disorders influence reproductive health, the effects of sleep on reproductive hormone concentrations are poorly characterized. We prospectively followed 259 regularly menstruating women across one to two menstrual cycles (the BioCycle Study, 2005-2007), measuring fasting serum hormone concentrations up to eight times per cycle. Women provided information about daily sleep in diaries and chronotype and night/shift work on a baseline questionnaire. We evaluated percent differences in mean hormone concentrations, the magnitude of shifts in the timing and amplitude of hormone peaks, and the risk for sporadic anovulation associated with self-reported sleep patterns and night/shift work. We estimated chronotype scores - categorizing women below and above the interquartile range (IQR) as "morning" and "evening" chronotypes, respectively. For every hour increase in daily sleep duration, mean estradiol concentrations increased by 3.9% (95% confidence interval [CI] 2.0, 5.9%) and luteal phase progesterone by 9.4% (CI 4.0, 15.2%). Receiving less than 7 hours of sleep per day was associated with slightly earlier rises in peak levels for several hormones. Women reporting night/shift work (n = 77) had lower testosterone relative to women employed without night/shift work (percent difference: -9.9%, CI -18.4, -0.4%). Women with morning chronotypes (n = 47) had earlier rises in estradiol during their cycles and potentially an earlier rise in luteinizing hormone. Compared to those who had intermediate chronotypes, women with evening chronotypes (n = 42) had a later luteinizing hormone peak of borderline statistical significance. A reduced risk for sporadic anovulation was suggested, but imprecise, for increasing hours of daily sleep leading up to ovulation (risk ratio 0.79, CI 0.59, 1.06), while an imprecise increased risk was observed for women with morning chronotypes (risk ratio 2.50, CI 0.93, 6.77). Sleep-related hormonal changes may not greatly alter ovarian function in healthy women, but have the potential to influence gynecologic health.
Women who experience pregnancy loss are especially prone to high stress, though the effects of stress on reproductive outcomes in this vulnerable population are unknown. We assessed relationships between perceived stress and hormones, anovulation, and fecundability among women with prior loss. One thousand two hundred fourteen women with 1-2 prior losses were followed for ≤6 cycles while attempting pregnancy and completed end-of-cycle stress assessments. For cycles 1 and 2, women also collected daily urine and completed daily perceived stress assessments. We assessed anovulation via. an algorithm based on human chorionic gonadotropin (hCG), pregnanediol-3-glucuronide (PdG), luteinizing hormone (LH), and fertility monitor readings. Pregnancy was determined via. hCG. Adjusted weighted linear mixed models estimated the effect of prospective phase-varying (menses, follicular, periovulatory, and luteal) perceived stress quartiles on estrone-1-glucuronide (E1G), PdG, and LH concentrations. Marginal structural models accounted for time-varying confounding by hormones and lifestyle factors affected by prior stress. Poisson and Cox regression estimated risk ratios and fecundability odds ratios of cycle-varying stress quartiles on anovulation and fecundability. Models were adjusted for age, race, body mass index (BMI), parity, and time-varying caffeine, alcohol, smoking, intercourse, and pelvic pain. Women in the highest versus lowest stress quartile had lower E1G and PdG concentrations, a marginally higher risk of anovulation [1.28; 95% confidence interval (CI) = 1.00, 1.63], and lower fecundability (0.71; 95% CI = 0.55, 0.90). Preconception perceived stress appears to adversely affect sex steroid synthesis and time to pregnancy. Mechanisms likely include the effects of stress on ovulatory function, but additional mechanisms, potentially during implantation, may also exist.
Purdue‐Smithe A et al., 2019·Current Developments in Nutrition·
Open Access
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. 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 8(th) week of gestation using weighted adjusted Cox proportional hazards models. 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. 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. 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.
Although minerals are linked to several reproductive outcomes, it is unknown whether dietary minerals are associated with ovulatory function. We hypothesised that low intakes of minerals would be associated with an increased risk of anovulation. We investigated associations between dietary mineral intake and both reproductive hormones and anovulation in healthy women in the BioCycle Study, which prospectively followed up 259 regularly menstruating women aged 18-44 years who were not taking mineral supplements for two menstrual cycles. Intakes of ten selected minerals were assessed through 24-h dietary recalls at up to four times per cycle in each participant. Oestradiol, progesterone, luteinising hormone (LH), follicle-stimulating hormone (FSH), sex-hormone-binding globulin and testosterone were measured in serum up to eight times per cycle. We used weighted linear mixed models to evaluate associations between minerals and hormones and generalised linear models for risk of anovulation. Compared with Na intake ≥1500 mg, Na intake <1500 mg was associated with higher levels of FSH (21·3 %; 95 % CI 7·5, 36·9) and LH (36·8 %; 95 % CI 16·5, 60·5) and lower levels of progesterone (-36·9 %; 95 % CI -56·5, -8·5). Na intake <1500 mg (risk ratio (RR) 2·70; 95 % CI 1·00, 7·31) and Mn intake <1·8 mg (RR 2·00; 95 % CI 1·02, 3·94) were associated with an increased risk of anovulation, compared with higher intakes, respectively. Other measured dietary minerals were not associated with ovulatory function. As essential minerals are mostly obtained via diet, our results comparing insufficient levels with sufficient levels highlight the need for future research on dietary nutrients and their associations with ovulatory cycles.
Is physical activity (PA) associated with fecundability in women with a history of prior pregnancy loss? Higher fecundability was related to walking among overweight/obese women and to vigorous PA in women overall. 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, 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 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, 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. 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. #NCT00467363.
Although maternal nutrition may affect fecundity, associations between preconception micronutrient levels and time to pregnancy (TTP) have not been examined. We assessed the relationship between preconception fat-soluble micronutrient concentrations and TTP among women with 1-2 prior pregnancy losses. This was a prospective cohort study of 1,228 women set within the Effects of Aspirin in Gestation and Reproduction (EAGeR) Trial (United States, 2007-2011), which assessed the association of preconception-initiated daily low-dose aspirin with reproductive outcomes. We measured preconception levels of zeaxanthin, cryptoxanthin, lycopene, αand β-carotene, and αand γ-tocopherol in serum. We used discrete Cox regression models, accounting for left-truncation and right-censoring, to calculate fecundability odds ratios and 95% confidence intervals. The models adjusted for age, body mass index, race, smoking, alcohol, physical activity, income, vitamin use, cholesterol, treatment arm, and study site. Serum α-carotene levels (per log unit (μg/dL) increase, fecundability odds ratio (FOR) = 1.17, 95% confidence interval (CI): 1.00, 1.36) and serum α-carotene concentrations at or above the US average (2.92 μg/dL) versus below the average (FOR = 1.21, 95% CI: 1.02, 1.44) were associated with shorter TTP. Compared with levels below the US average (187 μg/dL), γ-tocopherol concentrations at or above the average were associated with longer TTP (FOR = 0.83, 95% CI: 0.69, 1.00). The potential for these nutrients to influence fecundability deserves further exploration.
How are concentrations of plasma homocysteine and serum folate associated with reproductive hormones and anovulation in regularly menstruating women? Higher homocysteine was associated with sporadic anovulation and hormonal changes that may be indicative of impaired ovulatory function, but higher serum folate was associated only with higher luteal phase progesterone. Higher folate levels as well as some variants in genes relevant to one-carbon metabolism, are associated with improved reproductive outcomes and responses to fertility treatment, but only a few small studies have explored the relationship between markers of one-carbon metabolism and menstrual cycle characteristics. STUDY DESIGN, SIZE, Duration: The BioCycle Study (2005-2007) is a prospective, longitudinal cohort of 259 regularly menstruating women not using hormonal contraceptives or dietary supplements who were followed for up to two menstrual cycles. PARTICIPANTS/MATERIALS, SETTING, Serum folate and reproductive hormones were measured up to eight times per cycle and plasma homocysteine up to three times. Linear mixed models were used to estimate associations between serum folate or plasma homocysteine and log-transformed reproductive hormone levels while accounting for multiple observations and cycles per woman. Generalized estimating equations were used to examine risk of sporadic anovulation. All models were adjusted for age, race, body mass index, cigarette and alcohol use, and energy and fiber intake. Main Higher plasma homocysteine concentrations were associated with lower total estradiol across the cycle (adjusted percent change per unit increase in homocysteine [aPC] -2.3%, 95% CI: -4.2, -0.03), higher follicle stimulating hormone around the time of expected ovulation (aPC 2.4%, 95% CI: 0.2, 4.7) and lower luteal phase progesterone (aPC -6.5%, 95% CI: -11.1, -1.8). Higher serum folate concentrations were associated with higher luteal phase progesterone (aPC per unit increase in folate 1.0%, 95% CI: 0.4, 1.6). Higher homocysteine concentrations at expected ovulation were associated with a 33% increased risk of sporadic anovulation. We observed no risk associated with decreased folate concentrations, but a higher ratio of folate to homocysteine at ovulation was associated with a 10% decreased risk of anovulation. LIMITATIONS, Our results are generalizable to healthy women with adequate serum folate levels. The independent influence of homocysteine should be confirmed in larger cohorts and among women with folate deficiency or increased risks of anovulation. If these findings are confirmed, it is possible that lowering homocysteine with B-vitamins through diet or supplementation could improve ovulatory function in some women. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by the Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health (Contract numbers: HHSN275200403394C, HHSN275201100002I and Task one HHSN27500001). None of the authors has any conflicts of interest to disclose.
Vitamin D is associated with markers of ovarian reserve in women of advanced reproductive age and
in vitro
studies suggest that vitamin D may influence anti‐mullerian hormone (AMH). Higher vitamin D levels are also associated with improved IVF outcomes in some studies. However, less is understood regarding associations with ovarian reserve or time to pregnancy among younger women or women without a history of infertility. Our purpose was to assess the relationships between vitamin D and AMH and fecundability among women with proven fecundity.
Secondary analysis of the EAGeR Trial, a multicenter, block‐randomized, double‐blind, placebo‐controlled clinical trial to evaluate the effect of preconception‐initiated daily low dose aspirin on reproductive outcomes in women with a history of pregnancy loss and normal fecundity. Participants were attempting pregnancy, aged 18–40 years, with 1–2 prior pregnancy losses and no history of infertility. We assessed 25‐OH vitamin D and AMH in serum at baseline (not pregnant) among 1185 women. AMH levels were log‐transformed for normality. Linear regression was used to estimate associations between vitamin D and AMH concentrations adjusting for age, body mass index, race, season, physical activity, and number of prior losses. Time to hCG detected pregnancy was assessed using Cox proportional hazard regression models for discrete survival time, accounting for left truncation and right censoring, to estimate fecundability odds ratios (FOR), adjusting for the same factors. A total of 163 women (13.8%) had deficient vitamin D levels (<20 ng/mL). Overall, vitamin D levels were not associated with AMH (percent change −1.6, 95% confidence interval [CI] −5.3%, 2.3% per 10 ng/mL). Vitamin D deficiency was also not associated with AMH (deficient: adjusted geometric mean AMH 2.51, 95% CI 2.20, 2.85 vs. inadequate/sufficient: 2.74, 95% CI 2.60, 2.89). There also were no significant associations observed between overall vitamin D levels or deficiency and fecundability (FOR 1.09, 95% CI 0.84, 1.42 comparing deficient vs. inadequate/sufficient) after adjustment. Vitamin D was not associated with AMH, time to pregnancy, or fecundability among women with proven fecundity. These results suggest that vitamin D is not associated with ovarian reserve or fecundability and that vitamin D supplementation may offer little clinical benefit for improving markers of ovarian reserve and fecundity.
Support or Funding Information
Intramural Research Program, DIPHR, NICHD, NIH