North American Preconception Cohort Study Research Articles

A preconception cohort study of sugar-sweetened beverage consumption and semen quality.

Dietary factors, including high sugar intake, may have adverse effects on male reproduction. Studies of the association between sugar-sweetened beverage (SSB) intake and semen quality have reported inconsistent results. We estimated the effects of SSB consumption on semen quality in a North American preconception cohort study. We analyzed baseline data from 690 males (n=1,247 samples) participating in Pregnancy Study Online (PRESTO) during 2015-2022. Participants aged ≥21 years completed a baseline questionnaire on which they reported information about intake of SSBs, including sodas, energy drinks, sports drinks, and fruit juices. After enrollment, we invited U.S. participants to a semen testing substudy, in which they collected and analyzed two samples using an at-home semen testing kit. We used linear regression models to estimate adjusted percent differences (%D) and 95% confidence intervals (CI) for associations of SSB intake with semen volume, sperm concentration, total sperm count (TSC), motility, and total motile sperm count (TMSC). We used modified Poisson regression models to estimate adjusted risk ratios (RRs) and 95% CIs for the association of SSB intake with World Health Organization semen parameter cut points. Relative to non-consumers of SSBs, those who consumed ≥7 SSBs/week had lower semen volume (%D=-6, 95% CI: -13, 0), sperm concentration (%D=-22, 95% CI: -38, 0), TSC (%D=-22, 95% CI: -38, -2), motility (%D=-4, 95% CI: -10, 2), and TMSC (%D=-25, 95% CI: -43, -2). High SSB consumers also had greater risks of low sperm concentration (≤16 million/mL; RR=1.89, 95% CI: 1.11, 3.21), low TSC (≤39 million; RR=1.75, 95% CI: 0.92, 3.33), low motility (≤42%; RR=1.23, 95% CI: 0.87, 1.75) and low TMSC (≤21 million; RR=1.95, 95% CI: 1.12, 3.38). Associations were stronger among participants with body mass index ≥ 25kg/m2 . Greater SSB consumption was associated with reduced semen quality in a North American preconception cohort.

Air pollution and fecundability in a North American preconception cohort study

BackgroundAnimal and epidemiologic studies indicate that air pollution may adversely affect fertility. However, the level of evidence is limited and specific pollutants driving the association are inconsistent across studies. MethodsWe used data from a web-based preconception cohort study of pregnancy planners enrolled during 2013–2019 (Pregnancy Study Online; PRESTO). Eligible participants self-identified as female, were aged 21–45 years, resided in the United States (U.S.) or Canada, and were trying to conceive without fertility treatments. Participants completed a baseline questionnaire and bi-monthly follow-up questionnaires until conception or 12 months. We analyzed data from 8,747 participants (U.S.: 7,304; Canada: 1,443) who had been trying to conceive for < 12 cycles at enrollment. We estimated residential ambient concentrations of particulate matter < 2.5 µm (PM2.5), nitrogen dioxide (NO2), and ozone (O3) using validated spatiotemporal models specific to each country. We fit country-specific proportional probabilities regression models to estimate the association between annual average, menstrual cycle-specific, and preconception average pollutant concentrations with fecundability, the per-cycle probability of conception. We calculated fecundability ratios (FRs) and 95% confidence intervals (CIs) and adjusted for individual- and neighborhood-level confounders. ResultsIn the U.S., the FRs for a 5-µg/m3 increase in annual average, cycle-specific, and preconception average PM2.5 concentrations were 0.94 (95% CI: 0.83, 1.08), 1.00 (95% CI: 0.93, 1.07), and 1.00 (95% CI: 0.93, 1.09), respectively. In Canada, the corresponding FRs were 0.92 (95% CI: 0.74, 1.16), 0.97 (95% CI: 0.87, 1.09), and 0.94 (95% CI: 0.80, 1.09), respectively. Likewise, NO2 and O3 concentrations were not strongly associated with fecundability in either country. ConclusionsNeither annual average, menstrual cycle-specific, nor preconception average exposure to ambient PM2.5, NO2, and O3 were appreciably associated with reduced fecundability in this cohort of pregnancy planners.

A North American study of anthropometric factors and semen quality

To evaluate the association between anthropometric measures and semen parameters. Cross-sectional study. General population, United States. Male participants aged ≥21 years. We analyzed data from 659 males (1,185 samples) participating in a semen testing substudy of Pregnancy Online Study (PRESTO), a North American preconception cohort study. After enrollment, we invited males aged ≥21 years to perform at-home semen testing using the Trak™ system. Participants reported selected anthropometric variables (current weight, height, waist circumference, and weight at age 17 years) and covariate data via online baseline questionnaire. We used generalized estimating equations models to estimate the percent difference in mean log-transformed semen parameter values and 95% confidence intervals (CI) for associations between selected anthropometric variables and semen volume (mL), sperm concentration (million/mL), and total sperm count (million), adjusting for socio-demographics, lifestyle factors, and medical history. We also evaluated WHO-defined thresholds for low semen quality. Percentage differences in mean log-transformed semen volume, sperm concentration, and total sperm count (95% CI) comparing current BMI ≥35 vs. <25 kg/m2 were -6.3 (-15.8, 4.3), -6.4 (-24.6, 16.2) and -12.2 (-31.1, 11.8), respectively. Percentage differences (95% CIs) comparing waist circumferences of ≥42 vs. <31 inches were -4.2 (-15.0, 8.0), -6.4 (-27.6, 21.0) and -10.4 (-31.9, 17.9) for semen volume, sperm concentration, and total sperm count, respectively. Greater adult weight gain since age 17 years was associated with reduced semen volume (≥25 vs. <5 kg: percent difference -9.7, 95% CI: -18.4, 0.1), but not sperm concentration or total sperm count. The highest categories of each anthropometric variable were generally associated with WHO-defined low total sperm count (≤39 million). Selected anthropometric factors were modestly associated with poorer semen quality.

Associations between Residential Greenspace and Fecundability in a North American Preconception Cohort Study.

Residential green space can have positive physiological effects on human health through various mechanisms, including reducing stress and/or depression or facilitating physical activity. Although green space has been consistently associated with improved birth outcomes in several studies, there has been limited study of its effect on other reproductive outcomes, including fertility. We examined associations between residential green space and fecundability, the per-cycle probability of conception. We analyzed data from 8,563 female participants enrolled between 2013 and 2019 in Pregnancy Study Online (PRESTO), a prospective preconception cohort study of North American couples attempting conception. Participants completed a baseline questionnaire on sociodemographic, behavioral, and reproductive factors, and bimonthly follow-up questionnaires for up to 12 months to ascertain pregnancies. Using geocoded addresses, we calculated residential green space exposure using the Normalized Difference Vegetation Index (NDVI) within 50-, 100-, 250-, and buffers across multiple temporal scales: annual maximum, seasonal maximum, and seasonal mean. We used proportional probabilities regression models to estimate fecundability ratios (FRs), adjusting for sociodemographic, behavioral, and neighborhood characteristics. We also evaluated the extent to which associations were mediated by reductions in perceived stress or depressive symptoms and increased physical activity. When comparing the highest () with the lowest () NDVI exposures within , we observed positive associations in the annual maximum NDVI [FR: 1.33; 95% confidence interval (CI): 1.06, 1.67] and seasonal maximum NDVI (FR: 1.19; 95% CI: 1.00, 1.41) models, but little association in the seasonal mean NDVI models (FR: 0.98; 95% CI: 0.73, 1.30). Restricted cubic splines showed evidence of nonlinearity in this association. Results were similar across buffer distances. Perceived stress, depressive symptoms, and physical activity explained of mediation across all NDVI metrics. In this cohort, greater residential green space was associated with a modest increase in fecundability. https://doi.org/10.1289/EHP10648.

Use of Chemical Hair Straighteners and Fecundability in a North American Preconception Cohort.

Chemical hair straighteners ("relaxers") are used by millions of North Americans, particularly women of color. Hair relaxers may contain endocrine-disrupting compounds, which can harm fertility. We evaluated the association between hair relaxer use and fecundability among 11,274 participants from Pregnancy Study Online (PRESTO), a North American preconception cohort study. During 2014-2022, participants completed a baseline questionnaire in which they reported their history of relaxer use and completed follow-up questionnaires every 8 weeks for 12 months or until pregnancy, whichever came first. We used multivariable-adjusted proportional probabilities regression models to estimate fecundability ratios (FRs) and 95% confidence intervals (CIs). Relative to never use, fecundability was lower among current (FR= 0.81, 95% CI: 0.64, 1.03) and former (FR= 0.89, 95% CI: 0.81, 0.98) users of hair relaxers. FRs for first use of hair relaxers at ages <10, 10-19, and ≥20 years were 0.73 (95% CI: 0.55, 0.96), 0.93 (95% CI: 0.83, 1.04), and 0.85 (95% CI: 0.74, 0.98), respectively. Fecundability was lowest among those with longer durations of use (≥10 years vs. never: FR= 0.71, 95% CI: 0.54, 0.91) and more frequent use (≥5 times/year vs. never: FR= 0.82, 95% CI: 0.60, 1.11), but associations were nonmonotonic. In this preconception cohort study, use of chemical hair straighteners was associated with slightly reduced fecundability.

Associations between Residential Proximity to Major Roads and Semen Quality: Results from a North American Preconception Cohort Study

Associations between Residential Proximity to Major Roads and Semen Quality: Results from a North American Preconception Cohort Study

The association between work hours, shift work, and job latitude with fecundability: A preconception cohort study.

The role of occupational stress on male fertility is understudied. We examined associations between male occupational stress and fecundability. We used data from Pregnancy Study Online (PRESTO), a North American preconception cohort study. At baseline (2013-2019), male participants aged ≥ 21 years completed a baseline questionnaire on employment status, hours worked per week, time of day worked (daytime, evening, nights, and changing or rotating shifts), and job title. We used the O*NET occupational database to rate independence by job title. Female partners were followed via bimonthly follow-up questionnaires for 12 months or until pregnancy. We restricted analyses to 1,818 couples attempting conception for ≤ 6 cycles at enrollment. We used proportional probabilities regression to estimate fecundability ratios (FRs) and 95% confidence intervals (CIs). The FR comparing unemployed with employed men was0.84 (95% CI: 0.62-1.14). Among employed men, FRs and 95% CIs for evening shift work, night shift work, and rotating shift work were 0.89 (95% CI: 0.68-1.17), 0.94 (95% CI: 0.66-1.33), and 0.91 (95% CI: 0.75-1.11) relative to daytime shift work. The FR for any nondaytime shift work was 0.91 (95% CI: 0.78-1.07). Total work hours (long or short) and job independence scores were not appreciably associated with fecundability. In conclusion, working nondaytime shifts and being unemployed were associated with slightly decreased fecundability. However, the variability in these estimates was substantial and the results were reasonably consistent with chance. Little association was observed for other occupation measures. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Predictive models of pregnancy based on data from a preconception cohort study.

Can we derive adequate models to predict the probability of conception among couples actively trying to conceive? Leveraging data collected from female participants in a North American preconception cohort study, we developed models to predict pregnancy with performance of ∼70% in the area under the receiver operating characteristic curve (AUC). Earlier work has focused primarily on identifying individual risk factors for infertility. Several predictive models have been developed in subfertile populations, with relatively low discrimination (AUC: 59-64%). Study participants were female, aged 21-45 years, residents of the USA or Canada, not using fertility treatment, and actively trying to conceive at enrollment (2013-2019). Participants completed a baseline questionnaire at enrollment and follow-up questionnaires every 2 months for up to 12 months or until conception. We used data from 4133 participants with no more than one menstrual cycle of pregnancy attempt at study entry. On the baseline questionnaire, participants reported data on sociodemographic factors, lifestyle and behavioral factors, diet quality, medical history and selected male partner characteristics. A total of 163 predictors were considered in this study. We implemented regularized logistic regression, support vector machines, neural networks and gradient boosted decision trees to derive models predicting the probability of pregnancy: (i) within fewer than 12 menstrual cycles of pregnancy attempt time (Model I), and (ii) within 6 menstrual cycles of pregnancy attempt time (Model II). Cox models were used to predict the probability of pregnancy within each menstrual cycle for up to 12 cycles of follow-up (Model III). We assessed model performance using the AUC and the weighted-F1 score for Models I and II, and the concordance index for Model III. Model I and II AUCs were 70% and 66%, respectively, in parsimonious models, and the concordance index for Model III was 63%. The predictors that were positively associated with pregnancy in all models were: having previously breastfed an infant and using multivitamins or folic acid supplements. The predictors that were inversely associated with pregnancy in all models were: female age, female BMI and history of infertility. Among nulligravid women with no history of infertility, the most important predictors were: female age, female BMI, male BMI, use of a fertility app, attempt time at study entry and perceived stress. Reliance on self-reported predictor data could have introduced misclassification, which would likely be non-differential with respect to the pregnancy outcome given the prospective design. In addition, we cannot be certain that all relevant predictor variables were considered. Finally, though we validated the models using split-sample replication techniques, we did not conduct an external validation study. Given a wide range of predictor data, machine learning algorithms can be leveraged to analyze epidemiologic data and predict the probability of conception with discrimination that exceeds earlier work. The research was partially supported by the U.S. National Science Foundation (under grants DMS-1664644, CNS-1645681 and IIS-1914792) and the National Institutes for Health (under grants R01 GM135930 and UL54 TR004130). In the last 3 years, L.A.W. has received in-kind donations for primary data collection in PRESTO from FertilityFriend.com, Kindara.com, Sandstone Diagnostics and Swiss Precision Diagnostics. L.A.W. also serves as a fibroid consultant to AbbVie, Inc. The other authors declare no competing interests. N/A.

A Prospective Study of Male Depression, Psychotropic Medication Use, and Fecundability.

We examined the associations of male depression and psychotropic medication use with fecundability in a North American preconception cohort study (2013–2020). Men aged ≥21 years completed a baseline questionnaire with questions on history of diagnosed depression, the Major Depression Inventory (MDI), and psychotropic medication use. Pregnancy status was updated via bimonthly female follow-up questionnaires until pregnancy or 12 menstrual cycles, whichever occurred first. Analyses were restricted to 2,398 couples attempting conception for ≤6 menstrual cycles at entry. We fit proportional probabilities models to estimate fecundability ratios (FRs) and 95% confidence intervals (CIs), adjusting for age (male and female), education, (male and female), race/ethnicity, physical activity, alcohol intake, body mass index, smoking, and having previously impregnated a partner. Nearly 12% of participants reported a depression diagnosis; 90.6% had low depressive symptoms (MDI <20), 3.5% had mild symptoms (MDI: 20–24), 2.7% had moderate symptoms (MDI: 25–29), and 3.3% had severe symptoms (MDI: ≥30). A total of 8.8% of participants reported current use of psychotropic medications. History of depression was associated with slightly reduced fecundability, although this result was also reasonably compatible with chance (FR = 0.89; 95% CI: [0.76, 1.04]). FRs for mild, moderate, and severe compared with low depressive symptoms were 0.89 (95% CI: [0.66, 1.21]), 0.90 (95% CI: [0.62, 1.31]), and 0.88 (95% CI: [0.65, 1.20]), respectively. This indicates little evidence of a dose–response relationship for depressive symptoms with fecundability, although estimates were imprecise. Current psychotropic medication use mediated 44% of the association between depressive symptoms and fecundability.

Associations between Residential Green Space and Fertility in a North American Preconception Cohort Study

BACKGROUND AND AIM: A growing body of epidemiological literature shows that exposure to green space (natural vegetation) may have positive effects on human health, including reproductive outcomes. Residential green space may improve health via reduced exposure to traffic-related air pollution, reduced depressive symptoms or stress levels, and increased physical activity. We hypothesize that increased exposure to green space may promote fecundability, a sensitive marker of fertility. METHODS: In a North American preconception cohort study (Pregnancy Study Online, PRESTO), we prospectively examined associations between residential green space (measured by satellite normalized difference vegetation index [NDVI] at a 30m resolution) and fecundability (per-cycle probability of conception) (n=8,790). From 2013 through 2019, women aged 21-45 years who were trying to conceive without fertility treatment completed online questionnaires every 8 weeks for up to 12 months. We followed participants until reported pregnancy or a censoring event (loss to follow-up, end of pregnancy attempt, initiation of fertility treatment, or 12 menstrual cycles), whichever event was first. Using geocoded residential addresses, we calculated annual maximum NDVI for 50m, 100m, 250m, and 500m buffers around each residence to quantify green space. We used proportional probabilities regression models to estimate fecundability ratios (FR), adjusting for sociodemographic and lifestyle characteristics. RESULTS:Using life table methods, 67.7% of participants conceived who were in the highest NDVI group for the 250m buffer (NDVI: 0.8-1.0; n=874), compared to only 62.0% of participants with the lowest NDVI group (NDVI: 0.0-0.2; n=162). When comparing participants with the highest to lowest NDVI values in the 250m buffer, adjusted models show an FR of 1.43 (95% CI: 1.04, 1.95). Restricted cubic splines show a nonlinear trend. Results are similar for other distance buffers. CONCLUSIONS:We present the first epidemiologic evidence that residential greenness is positively associated with fecundability. Future work will examine the role of key pathways that may mediate this relationship. KEYWORDS: Green space, Reproductive Outcomes, Female, Built environment, Environmental disparities

Changes in Behavior with Increasing Pregnancy Attempt Time: A Prospective Cohort Study.

The extent to which couples change their behaviors with increasing pregnancy attempt time is not well documented. We examined change in selected behaviors over pregnancy attempt time in a North American preconception cohort study. Eligible females were ages 21-45 years and not using fertility treatment. Participants completed baseline and bimonthly follow-up questionnaires for up to 12 months or until pregnancy. Among 3,339 females attempting pregnancy for 0-1 cycles at enrollment, 250 contributed 12 months of follow-up without conceiving. Comparing behaviors at 12 months versus baseline, weighted for loss-to-follow-up, we observed small-to-moderate reductions in mean caffeine intake (-19.5 mg/day, CI = -32.7, -6.37), alcohol intake (-0.85 drinks/week, CI = -1.28, -0.43), marijuana use (-3.89 percentage points, CI = -7.33, 0.46), and vigorous exercise (-0.68 hours/week, CI = -1.05, -0.31), and a large increase in activities to improve conception chances (e.g., ovulation testing) (21.7 percentage points, CI = 14.8, 28.6). There was little change in mean cigarette smoking (-0.27 percentage points, CI = -1.58, 1.04), perceived stress scale score (-0.04 units, CI = -0.77, 0.69), or other factors (e.g., sugar-sweetened soda intake, moderate exercise, intercourse frequency, and multivitamin use), but some heterogeneity within subgroups (e.g., 31% increased and 32% decreased their perceived stress scores by ≥2 units; 14% reduced their smoking but none increased their smoking by ≥5 cigarettes/day). Although many behaviors changed with increasing pregnancy attempt time, mean changes tended to be modest for most variables. The largest differences were observed for the use of caffeine, alcohol, and marijuana, and methods to improve conception chances.

Pesticide residue intake from fruits and vegetables and fecundability in a North American preconception cohort study

Intake of conventionally-grown fruits and vegetables with higher levels of pesticide residue contamination has been associated with poorer semen quality and lower probability of live birth among couples undergoing fertility treatment. We examined the association between dietary intake of pesticide residues and fecundability, the per cycle probability of conception, in a preconception cohort of pregnancy planners. We enrolled women aged 21–45 years who were attempting to conceive without use of fertility treatment into Pregnancy Study Online (PRESTO) from June 2013 through September 2019. Participants completed a baseline questionnaire on demographics, lifestyle factors, and medical and reproductive histories, and bimonthly follow-up questionnaires for up to 12 months or until reported conception. Ten days after baseline, participants completed the National Cancer Institute’s Diet History Questionnaire II, a validated food frequency questionnaire. Using data from the USDA Pesticide Data Program, we classified fruits and vegetables as having high or low pesticide residues using a validated method. We examined the relation between greater intake of high- and low-pesticide residue fruits and vegetables with fecundability using proportional probabilities regression models, adjusted for potential confounders and accounting for consumption of organic produce. We restricted our analysis to 5234 women who had been attempting conception for ≤6 cycles at study entry, and further stratified by pregnancy attempt time at study entry (<3 vs. 3–6 cycles) to evaluate potential for reverse causation. Intakes of high- and low-pesticide residue fruits and vegetables were not appreciably related to fecundability in the full sample, or among women trying to conceive for <3 cycles at study entry. However, among women trying to conceive for 3–6 cycles at study entry, both high- and low-pesticide residue fruit and vegetable intakes were strongly inversely related to fecundability, indicating potential reverse causation bias. These results do not support the hypothesis that intake of pesticide residues from conventionally-grown fruits and vegetables is harmful to fertility, although non-differential exposure misclassification may have attenuated our findings.

Menstrual patterns and self-reported hirsutism as assessed via the modified Ferriman-Gallwey scale: A cross-sectional study

ObjectiveHirsutism, the presence of excess terminal hair in a male pattern, is a clinical marker of androgen excess in women. We used cross-sectional data from a North American preconception cohort study to evaluate the association between menstrual cycle characteristics and hirsutism. Study DesignWomen aged 21–45 years were recruited to a North American cohort of pregnancy planners. On the baseline questionnaire, participants self-reported menstrual characteristics, which included menstrual regularity, cycle length, bleed length, and bleed heaviness. Participants provided a self-rating of hirsutism in nine distinct body areas using pictograms representing the modified Ferriman-Gallwey (mFG) score. Using their ratings, we calculated total mFG scores and defined hirsutism as mFG scores ≥8. We used log-binomial regression models to estimate prevalence ratios (PRs) for the association between menstrual characteristics and hirsutism assessed at baseline. ResultsWe included 5,542 women in the analytic cohort. Mean mFG score was 4.7, with 21.7 % reporting mFG scores ≥8. Compared with women with regular menstrual cycles, irregular cycles were positively associated with mFG ≥8 (PR 1.73, 95 % CI 1.56–1.91). Bleed lengths of ≥7 days compared with <3 days also showed a positive association with mFG score ≥8 (PR 1.59, 95 % CI 1.16–2.19), as did heavy bleeds (PR 1.42, 95 % CI 1.21–1.67) compared with moderate bleeds. Findings remained consistent when restricted to women without a prior diagnosis of polycystic ovary syndrome. ConclusionsIn a population-based cohort of North American women, menstrual irregularity, increased cycle and bleeds lengths, and heavier menstrual bleeds were associated with self-reported hirsutism.

Fecundability in relation to use of fertility awareness indicators in a North American preconception cohort study

To quantify the frequency of use of selected fertility awareness indicators and to assess their influence on fecundability. Web-based prospective cohort study. Not applicable. Female pregnancy planners, aged 21-45years, attempting conception for ≤6 cycles at study entry. None. We ascertained time to pregnancy, in menstrual cycles, with bimonthly questionnaires. We estimated adjusted fecundability ratios (FRs) and confidence intervals (CIs) using proportional probabilities models, controlling for age, income, education, smoking, intercourse frequency, and other lifestyle and reproductive factors. A total of 5,688 women were analyzed, with a mean age of 29.9years and mean time trying of 2.1 cycles at baseline; 30% had ever been pregnant. At baseline, 75% were using one or more fertility indicators (counting days or charting menstrual cycles [71%], measuring basal body temperature [BBT, 21%], monitoring cervical fluid [39%], using urine LH tests [32%], or feeling for changes in position of the cervix [12%]). Women using any fertility indicator at baseline had higher subsequent fecundability (adjusted FR 1.25, 95% CI 1.16-1.35) than those not using any fertility indicators. For each individual indicator, adjusted FRs ranged from 1.28-1.36, where 1.00 would indicate no relation with fecundability. The adjusted FR for women using a combination of charting days, cervical fluid, and urine LH was 1.48 (95% CI 1.31-1.67) relative to women using no fertility indicators. In a North American preconception cohort study, use of fertility indicators indicating the fertile window was common, and was associated with greater fecundability.

Dietary cadmium intake and fecundability in a North American preconception cohort study

Dietary cadmium intake and fecundability in a North American preconception cohort study

Female sleep patterns, shift work, and fecundability in a North American preconception cohort study

To prospectively evaluate the association between female sleep patterns, shift work, and fecundability. Web-based preconception cohort study, Pregnancy Study Online (PRESTO). Not applicable. North American Women aged 21-45years attempting pregnancy. Not applicable. At baseline, self-reported average sleep duration per 24-hour period in the previous month, the frequency of trouble sleeping within the last 2weeks (as measured by the Major Depression Inventory), and shift work patterns. Pregnancy status determined by follow-up questionnaires completed every 8weeks for up to 12months or until conception. The analyses were restricted to 6,873 women attempting pregnancy for ≤6months at enrollment from June 2013 through September 2018. We used proportional probabilities regression models to estimate fecundability ratios (FRs) and 95% confidence intervals (CIs), adjusting for potential confounders. Relative to 8hours of sleep per day, FRs for <6, 6, 7, and ≥9hours of sleep/day were 0.89 (95% CI, 0.75-1.06), 0.95 (95% CI, 0.86-1.04), 0.99 (95% CI, 0.92-1.06), and 0.96 (95% CI, 0.84-1.10), respectively. Compared with no trouble sleeping, FRs for trouble sleeping <50% of the time or trouble sleeping >50% of the time were 0.93 (95% CI, 0.88-1.00) and 0.87 (95% CI, 0.79-0.95), respectively. The results were slightly stronger among women with higher depressive symptoms and perceived stress levels. There was no association between shift work and fecundability. Trouble sleeping at night was associated with modestly reduced fecundability. A weaker inverse association was observed between shorter sleep duration and fecundability.

Male sleep duration and fecundability in a North American preconception cohort study

To evaluate prospectively the association between male sleep duration and fecundability. Pregnancy Online Study (PRESTO), a Web-based prospective cohort study of North American couples enrolled during the preconception period (2013-2017). Not applicable. Male participants were aged ≥21years; female participants were aged 21-45years. None. At enrollment, men reported their average nightly sleep duration in the previous month. Pregnancy status was updated on female follow-up questionnaires every 8weeks for up to 12months or until conception. Analyses were restricted to 1,176 couples who had been attempting to conceive for up to six cycles at enrollment. Proportional probabilities regression models were used to estimate fecundability ratios (FRs) and 95% confidence intervals (CIs), adjusting for potential confounders. Relative to 8hours per night of sleep, multivariable-adjusted FRs for <6, 6, 7, and ≥9hours per night of sleep were 0.62 (95% CI 0.45-0.87), 1.06 (95% CI 0.87-1.30), 0.97 (95% CI 0.81-1.17), and 0.73 (95% CI 0.46-1.15), respectively. The association between short sleep duration (<6hours per night) and fecundability was similar among men not working nights or rotating shifts (FR 0.60, 95% CI 0.41-0.88) and among men without a history of infertility (FR 0.62, 95% CI 0.44-0.87) and was stronger among fathers (FR 0.46, 95% CI 0.28-0.76). Short sleep duration in men was associated with reduced fecundability. Because male factor accounts for 50% of couple infertility, identifying modifiable determinants of infertility could provide alternatives to expensive fertility workups and treatments.

Age and fecundability in a North American preconception cohort study

There is a well-documented decline in fertility treatment success with increasing female age; however, there are few preconception cohort studies that have examined female age and natural fertility. In addition, data on male age and fertility are inconsistent. Given the increasing number of couples who are attempting conception at older ages, a more detailed characterization of age-related fecundability in the general population is of great clinical utility. The purpose of this study was to examine the association between female and male age with fecundability. We conducted a web-based preconception cohort study of pregnancy planners from the United States and Canada. Participants were enrolled between June 2013 and July 2017. Eligible participants were 21-45 years old (female) or ≥21 years old (male) and had not been using fertility treatments. Couples were followed until pregnancy or for up to 12 menstrual cycles. We analyzed data from 2962 couples who had been trying to conceive for ≤3 cycles at study entry and reported no history of infertility. We used life-table methods to estimate the unadjusted cumulative pregnancy proportion at 6 and 12 cycles by female and male age. We used proportional probabilities regression models to estimate fecundability ratios, the per-cycle probability of conception for each age category relative to the referent (21-24 years old), and 95% confidence intervals. Among female patients, the unadjusted cumulative pregnancy proportion at 6 cycles of attempt time ranged from 62.0% (age 28-30 years) to 27.6% (age 40-45 years); the cumulative pregnancy proportion at 12 cycles of attempt time ranged from 79.3% (age 25-27 years old) to 55.5% (age 40-45 years old). Similar patterns were observed among male patients, although differences between age groups were smaller. After adjusting for potential confounders, we observed a nearly monotonic decline in fecundability with increasing female age, with the exception of 28-33 years, at which point fecundability was relatively stable. Fecundability ratios were 0.91 (95% confidence interval, 0.74-1.11) for ages 25-27, 0.88 (95% confidence interval, 0.72-1.08) for ages 28-30, 0.87 (95% confidence interval, 0.70-1.08) for ages 31-33, 0.82 (95% confidence interval, 0.64-1.05) for ages 34-36, 0.60 (95% confidence interval, 0.44-0.81) for ages 37-39, and 0.40 (95% confidence interval, 0.22-0.73) for ages 40-45, compared with the reference group (age, 21-24 years). The association was stronger among nulligravid women. Male age was not associated appreciably with fecundability after adjustment for female age, although the number of men >45 years old was small (n=37). In this preconception cohort study of North American pregnancy planners, increasing female age was associated with an approximately linear decline in fecundability. Although we found little association between male age and fecundability, the small number of men in our study >45 years old limited our ability to draw conclusions on fecundability in older men.

Sleep and male fecundity in a north American preconception cohort study

Sleep and male fecundity in a north American preconception cohort study

Body mass index, physical activity and fecundability in a North American preconception cohort study

To evaluate the association between adiposity, physical activity (PA), and fecundability. Prospective cohort study. Not applicable. A total of 2,062 female pregnancy planners from the United States and Canada who were enrolled during the preconception period. None. Self-reported pregnancy. Fecundability ratios (FRs) and 95% confidence intervals (CIs) were estimated using proportional probabilities models that adjusted for potential confounders. Relative to body mass index (BMI) 18.5-24kg/m(2), FRs for BMI <18.5, 25-29, 30-34, 35-39, 40-44, and ≥45kg/m(2) were 1.05 (95% CI 0.76-1.46), 1.01 (95% CI 0.89-1.15), 0.98 (95% CI 0.82-1.18), 0.78 (95% CI 0.60-1.02), 0.61 (95% CI 0.42-0.88), and 0.42 (95% CI 0.23-0.76), respectively. Reduced fecundability was observed among women with the largest waist-to-hip ratios (≥0.85 vs. <0.75; FR = 0.87, 95% CI 0.74-1.01) and waist circumferences (≥36 vs. <26 inches [≥90 vs. <66 cm]; FR = 0.80, 95% CI 0.59-1.01). Tendency to gain weight in the chest/shoulders (FR = 0.63, 95% CI 0.36-1.08) and waist/stomach (FR = 0.90, 95% CI 0.79-1.02), relative to hips/thighs, was associated with lower fecundability. Moderate PA was associated with increased fecundability (≥5 vs. <1h/wk; FR = 1.26, 95% CI 0.96-1.65), but there was no dose-response relation. Among overweight/obese women (BMI ≥25kg/m(2)), fecundability was 27% higher for vigorous PA of ≥5 versus <1h/wk (95% CI 1.02-1.57). Various measures of overall and central adiposity were associated with decreased fertility among pregnancy planners. Vigorous PA was associated with improved fertility among overweight and obese women only; moderate PA was associated with improved fertility among all women.