Association of income and education with fecundability in a North American preconception cohort

Experiences of discrimination across the life course among pregnancy planners in the United States and Canada

Little is known about discrimination among pregnancy planners. We used questionnaire data from Pregnancy Study Online (PRESTO), a preconception cohort study, to characterize experiences, attributions, and responses to discrimination (n = 10,460). Eligible participants were assigned female at birth, aged 21-45 years, U.S. or Canadian residents, and not using contraception or fertility treatment. Participants completed a supplemental questionnaire (2013-2024) that included the Philadelphia Urban ACE Survey, Williams' Everyday Discrimination and Major Experiences of Discrimination scales, and Krieger's instrument on responses to discrimination. Mean age at enrollment was 30.9 years. Overall, 83.8 % of participants identified as non-Hispanic White, and 50.4 % had ≥17 years education. Discrimination across the life course varied: 11 % of participants reported childhood racial discrimination, 80.3 % reported ever experiencing everyday discrimination, and 47.2 % reported ever experiencing lifetime discrimination. The most prevalent types of everyday discrimination included being perceived as not smart (63.4 %) and being treated with disrespect (62.6 %), while job-related discrimination was the most frequently-reported lifetime experience (33.9 %). Most Black participants (non-Hispanic and Hispanic) reported their race or ethnicity as one of the main reasons they were discriminated against (87.7 % and 80 %, respectively), while sex or gender was most commonly-reported by other racial and ethnic groups (range: 75.9-82.4 %). Most participants responded passively to discrimination: keeping it to themselves and accepting it as a fact of life (37.4 %). All participants other than non-Hispanic White reported greater exposure to discrimination across the life course, and attributions for discrimination (e.g., race, gender, education, income level) varied across racial and ethnic groups.

One-carbon metabolism, insulin resistance, and fecundability in a Singapore prospective preconception cohort study

BACKGROUND

One-carbon metabolism, which consists of the folate cycle, methionine cycle, and trans-sulphuration pathway, is associated with nucleotide synthesis. However, the association between one-carbon metabolites, metabolic status, and reproductive health remains poorly understood.

OBJECTIVES

We examined the association between the one-carbon cycle plasma metabolites and fecundability and determined whether it is modified by metabolic health status, as assessed by insulin resistance (IR).

METHODS

This prospective cohort study utilized data from the Singapore PREconception Study of long-Term maternal and child Outcomes. Fasting blood samples were collected, and one-carbon cycle metabolites were measured. Fecundability was measured by time to pregnancy in menstrual cycles within a year of enrollment. We identified patterns in plasma one-carbon cycle metabolites using principal component (PC) analysis. We estimated fecundability ratios (FRs) and confidence intervals (CIs), with confounder adjustment using discrete-time proportional hazards models. IR was determined using the Homeostatic Model Assessment 2 Insulin Resistance score, classified into lower IR (<0.65) and higher IR (≥0.65). The role of IR was examined through interaction tests and stratification.

RESULTS

We identified 3 one-carbon cycle PCs. PC1, characterized by higher folate and lower homocysteine concentrations; PC2, characterized by higher concentrations of dimethylglycine, choline, methionine, and betaine; and PC3, characterized by higher concentrations of vitamins B2, B12, and B6. Each z-score increase in PC1 was associated with a 17% increase in fecundability (FR: 1.17; 95% CI: 1.03, 1.33). The association between PC1 and fecundability was more evident in women with lower IR (FR: 1.30; 95% CI: 1.08, 1.57) but was attenuated in those with higher IR (FR: 1.09; 95% CI: 0.92, 1.30), with a P-for-interaction of 0.127. PC2 and PC3 were not associated with fecundability.

CONCLUSIONS

Our findings suggest that higher folate and lower homocysteine concentrations, which reflected the interlinked folate and methionine cycles, were associated with higher fecundability in preconception women with lower IR but less so in those with higher IR.

CLINICAL TRIAL REGISTRATION

This trial was registered at ClinicalTrials.gov as NCT03531658 (https://www.

CLINICALTRIALS

gov/study/NCT03531658).

Lifecourse Socioeconomic Status and High-Risk Pregnancy in Chinese Women: Evidence From Grandmothers, Mothers, and Their Children's Health Study

INTRODUCTION

The increasing proportion of women with high-risk pregnancy has been highlighted as an important public health challenge. This study examined the associations between maternal socioeconomic status during childhood, young adulthood, and married life and the risk of the spectrum of high-risk pregnancy in Chinese pregnant women.

METHODS

This study used data from the Grandmothers, Mothers, and Their Children's Health study, which was conducted in Huai'an city, China, from 2020 to 2021 and included 8,407 married pregnant women. High-risk pregnancy was defined according to the Five-Color Management framework by linking to the Maternity Information System. Maternal socioeconomic status across the life course was constructed using the educational levels of maternal parents, maternal family economic status at age 18 years (referring to parents' economic status), maternal educational level, maternal occupation, husband's educational level, and annual household income. Logistic regression models, the Shapley value decomposition, and the serial mediation model were used. Analyses were conducted in 2024.

RESULTS

There were dose-response associations between socioeconomic status scores and high-risk pregnancy at each stage of maternal life, including childhood, young adulthood, and married life (p for trend<0.05). Married life socioeconomic status accounted for 79.59% of the model's explanatory power, followed by young adulthood (10.84%) and childhood socioeconomic status (9.57%). Compared with those with consistently high socioeconomic status, women with consistently low socioeconomic status had higher odds of developing high-risk pregnancy (OR=1.63, 95% CI=1.32, 2.01).

CONCLUSIONS

Women with lower socioeconomic status across their life-course, particularly those with consistently low socioeconomic status, have a higher risk of high-risk pregnancy. Married life socioeconomic status accounts for the largest portion of the explanatory power of the model. Reducing socioeconomic inequalities from a life-course perspective and promoting universal access to healthcare resources should be considered in the implementation of universal two-child and three-child policies in China.

Female sexual function and distress and time-to-pregnancy in a prospective preconception cohort

BACKGROUND

Fertility success among mixed-sex couples often depends on frequency and timing of sexual intercourse, yet little research has evaluated the association between preconception sexual function and time-to-pregnancy.

OBJECTIVE

To evaluate the effects of female sexual dysfunction, distress related to sexual functioning, and painful intercourse on time-to-pregnancy.

STUDY DESIGN

We followed 2500 participants from Pregnancy Study Online, a prospective cohort study of self-identified females attempting pregnancy without the use of fertility treatments. Participants enrolled between 2021 and 2024. Thirty days after enrollment, participants completed a supplemental questionnaire that contained questions about sexual health, including a modified version of the 6-item Female Sexual Function Index (score range 2-30, score ≤19 defined as sexual dysfunction) and the Female Sexual Distress Scale (score range 0-48, score ≥20 defined as clinically relevant distress), which assess experiences in the previous 4 weeks. Participants completed the supplemental questionnaire no later than 6 months after initiating conception attempts. We estimated time-to-pregnancy based on self-reported pregnancy status on follow-up questionnaires completed every 8 weeks for up to 12 months. We used proportional probabilities regression to calculate fecundability ratios and 95% confidence intervals relating exposure measures with time-to-pregnancy, adjusting for a range of prespecified confounders. As an exploratory analysis, we evaluated individual domains of sexual function (ie, interest, arousal, orgasm, lubrication, and satisfaction) in relation to time-to-pregnancy.

RESULTS

The study population was primarily non-Hispanic White, high income, with college or graduate education. Exposure prevalence was 20.1% for female sexual dysfunction, 8.8% for distress, and 29.6% for any pain with intercourse. We observed no association between female sexual dysfunction and time-to-pregnancy (adjusted fecundability ratio 1.00, 95% confidence interval 0.890, 1.13) when female sexual dysfunction was defined using a clinically validated cut point, but observed that those in the first, second, and third quartile of scores had delayed conception compared to those in the fourth (highest function) (adjusted fecundability ratios 0.90, 95% confidence interval 0.76, 1.06; 0.88, 95% confidence interval 0.75, 1.04; and 0.90, 95% confidence interval 0.77, 1.04, respectively). We found 18% reduced fecundability among those with sexual distress as defined by a clinically validated cut point compared to those without (adjusted fecundability ratio 0.82, 95% confidence interval 0.69, 0.98). Participants reporting painful intercourse most or all the time had a longer time-to-pregnancy than those reporting no pain (adjusted fecundability ratio 0.81, 95% confidence interval 0.62, 1.06). In exploratory analyses, lower function in orgasm and lubrication domains, but not interest, desire, and arousal, were associated with longer time-to-pregnancy.

CONCLUSION

Preconception sexual dysfunction, specifically distress and frequent painful intercourse, was associated with delayed conception. Preconception clinical assessment of sexual function, including discussion of individual domains of sexual function, may elucidate important modifiable issues.

Residential Proximity to Oil and Gas Development and Mental Health in a North American Preconception Cohort Study: 2013-2023

Objectives. To evaluate associations between oil and gas development (OGD) and mental health using cross-sectional data from a preconception cohort study, Pregnancy Study Online. Methods. We analyzed baseline data from a prospective cohort of US and Canadian women aged 21 to 45 years who were attempting conception without fertility treatment (2013-2023). We developed residential proximity measures for active OGD during preconception, including distance from nearest site. At baseline, participants completed validated scales for perceived stress (10-item Perceived Stress Scale, PSS) and depressive symptoms (Major Depression Inventory, MDI) and reported psychotropic medication use. We used log-binomial regression and restricted cubic splines to estimate prevalence ratios (PRs) and 95% confidence intervals (CIs). Results. Among 5725 participants across 37 states and provinces, residence at 2 km versus 20 to 50 km of active OGD was associated with moderate to high perceived stress (PSS ≥ 20 vs < 20: PR = 1.08; 95% CI = 0.98, 1.18), moderate to severe depressive symptoms (MDI ≥ 20 vs < 20: PR = 1.27; 95% CI = 1.11, 1.45), and psychotropic medication use (PR = 1.11; 95% CI = 0.97, 1.28). Conclusions. Among North American pregnancy planners, closer proximity to OGD was associated with adverse preconception mental health symptomatology. (Am J Public Health. 2024;114(9):923-934. https://doi.org/10.2105/AJPH.2024.307730).

Association between job control and time to pregnancy in a preconception cohort

OBJECTIVE

To evaluate associations between low job control (operationalized as job independence and freedom to make decisions) and time to pregnancy. Low job control, a form of workplace stress, is associated with adverse health outcomes ranging from cardiovascular disease to premature mortality; few studies have specifically examined its association with reproductive outcomes.

DESIGN

We used data from Pregnancy Study Online, an internet-based preconception cohort study of couples trying to conceive in the United States and Canada. We estimated fecundability ratios (FRs) and 95% confidence intervals (CIs) via proportional probability regression models, adjusting for sociodemographic and behavioral characteristics.

SETTING

Not applicable (Web-based study).

PATIENTS

Participants self-identified as female, were aged 21-45 years, and reported ≤6 cycles of pregnancy attempt time at enrollment (2018-2022).

EXPOSURE

We assessed job control by matching participants' baseline self-reported occupation and industry with standardized occupation codes from the National Institute for Occupational Safety and Health's Industry and Occupation Computerized Coding System, then linking codes to O∗NET job exposure scores for job independence and freedom to make decisions.

MAIN OUTCOME MEASURE

Our main outcome measure was fecundability. Participants completed self-administered questionnaires at baseline and every 8 weeks for up to 12 months or until reported pregnancy, whichever occurred first.

RESULTS

Among 3,110 participants, lower job independence was associated with reduced fecundability. Compared with the fourth (highest) quartile, corresponding to the most job independence, FRs (95% CI) for first (lowest), second, and third quartiles were 0.92 (0.82-1.04), 0.84 (0.74-0.95), and 0.99 (0.88, 1.11), respectively. Lower freedom to make decisions was associated with slightly reduced fecundability (first vs. fourth quartile: FR = 0.92; 95% CI: 0.80-1.05).

CONCLUSION

Lower job control, a work-related stressor, may adversely influence time to pregnancy. Because job control is a condition of work (i.e., not modifiable by individuals), these findings may strengthen arguments for improving working conditions as a means of improving worker health, including fertility.

Time to pregnancy and life expectancy: a cohort study of 18 796 pregnant couples

STUDY QUESTION

Is fecundity, measured as time to pregnancy (TTP), associated with mortality in parents?

SUMMARY ANSWER

Prolonged TTP is associated with increased mortality in both mothers and fathers in a dose-response manner.

WHAT IS KNOWN ALREADY

Several studies have linked both male and female fecundity to mortality. In women, infertility has been linked to several diseases, but studies suggest that the underlying conditions, rather than infertility, increase mortality.

STUDY DESIGN, SIZE, DURATION

A prospective cohort study was carried out on 18 796 pregnant couples, in which the pregnant women attended prophylactic antenatal care between 1973 and 1987 at a primary and tertiary care unit. The couples were followed in Danish mortality registers from their child's birth date until death or until 2018. The follow-up period was up to 47 years, and there was complete follow-up until death, emigration or end of study.

PARTICIPANTS/MATERIALS, SETTING, METHODS

At the first antenatal visit, the pregnant women were asked to report the time to the current pregnancy. Inclusion was restricted to the first pregnancy, and TTP was categorised into <12 months, ≥12 months, not planned, and not available. In sub-analyses, TTP ≥12 was further categorized into 12-35, 36-60, and >60 months. Information for parents was linked to several Danish nationwide health registries. Survival analysis was used to estimate the hazard ratios (HRs) with a 95% CI for survival and adjusted for age at the first attempt to become pregnant, year of birth, socioeconomic status, mother's smoking during pregnancy, and mother's BMI.

MAIN RESULTS AND THE ROLE OF CHANCE

Mothers and fathers with TTP >60 months survived, respectively, 3.5 (95% CI: 2.6-4.3) and 2.7 (95% CI: 1.8-3.7) years shorter than parents with a TTP <12 months. The mortality was higher for fathers (HR: 1.21, 95% CI: 1.09-1.34) and mothers (HR: 1.29, 95% CI: 1.12-1.49) with TTP ≥12 months compared to parents with TTP <12 months. The risk of all-cause mortality during the study period increased in a dose-response manner with the highest adjusted HR of 1.98 (95% CI: 1.62-2.41) for fathers and 2.03 (95% CI: 1.56-2.63) for mothers with TTP >60 months. Prolonged TTP was associated with several different causes of death in both fathers and mothers, indicating that the underlying causes of the relation between fecundity and survival may be multi-factorial.

LIMITATIONS, REASONS FOR CAUTION

A limitation is that fecundity is measured using a pregnancy-based approach. Thus, the cohort is conditioned on fertility success and excludes sterile couples, unsuccessful attempts and spontaneous abortions. The question used to measure TTP when the pregnant woman was interviewed at her first attended prophylactic antenatal care: 'From the time you wanted a pregnancy until it occurred, how much time passed?' could potentially have led to serious misclassification if the woman did not answer on time starting unprotected intercourse but on the start of wishing to have a child.

WIDER IMPLICATIONS OF THE FINDINGS

We found that TTP is a strong marker of survival, contributing to the still-emerging evidence that fecundity in men and women reflects their health and survival potential.

STUDY FUNDING/COMPETING INTEREST(S)

The authors acknowledge an unrestricted grant from Ferring. The funder was not involved in the study design, collection, analysis, interpretation of data, the writing of this article, or the decision to submit it for publication. M.L.E. is an advisor to Ro, VSeat, Doveras, and Next.

TRIAL REGISTRATION NUMBER

N/A.

Optimizing preconception care and interventions for improved population health

There is growing literature indicating that optimal preconception health is associated with improved reproductive, perinatal, and pediatric outcomes. Given that preconception care is recommended for all individuals planning a pregnancy, medical providers and public health practitioners have a unique opportunity to optimize care and improve health outcomes for reproductive-aged individuals. Knowledge of the determinants of preconception health is important for all types of health professionals, including policy makers. Although some evidence-based recommendations have already been implemented, additional research is needed to identify factors associated with favorable health outcomes and to ensure that effective interventions are made in a timely fashion. Given the largely clinical readership of this journal, this piece is primarily focused on clinical care. However, we acknowledge that optimizing preconception health for the entire population at risk of pregnancy requires broadening our strategies to include population-health interventions that consider the larger social systems, structures, and policies that shape individual health outcomes.

The Relationship Between Contraceptive Method Use and Return of Fecundity Among Women Attempting Pregnancy in Low- and Middle-Income Countries

One of the most common barriers to using effective family planning methods is the belief that hormonal contraceptives and contraceptive devices have adverse effects on future fertility. Recent evidence from high-income settings suggests that some hormonal contraceptive methods are associated with delays in return of fecundity, yet it is unclear if these findings generalize to low- and middle-income populations, especially in regions where the injectable is widely used and pressure to bear children is significant. Using reproductive calendar data pooled across 47 Demographic and Health Surveys, we find that the unadjusted 12-month probability of pregnancy for women attempting pregnancy after discontinuing traditional methods, condoms, the pill, and the IUD ranged from 86% to 91%. The 12-month probability was lowest among those who discontinued injectables and implants, with approximately 1 out of 5 women not becoming pregnant within one year after discontinuation. Results from multivariable analysis showed that compared with users of either periodic abstinence or withdrawal, users of the pill, IUD, injectable, and implant had lower fecundability following discontinuation, with the largest reductions occurring among women who used injectables and implants. These findings indicate that women's concerns about potential short-term reductions in fecundity following contraceptive use are not unfounded.

Socioeconomic status and fecundability in a Danish preconception cohort

STUDY QUESTION

To what extent is socioeconomic status (SES), as measured by educational attainment and household income, associated with fecundability in a cohort of Danish couples trying to conceive?

SUMMARY ANSWER

In this preconception cohort, lower educational attainment and lower household income were associated with lower fecundability after adjusting for potential confounders.

WHAT IS KNOWN ALREADY

Approximately 15% of couples are affected by infertility. Socioeconomic disparities in health are well established. However, little is known about socioeconomic disparity and its relation to fertility.

STUDY DESIGN, SIZE, DURATION

This is a cohort study of Danish females aged 18-49 years who were trying to conceive between 2007 and 2021. Information was collected via baseline and bi-monthly follow-up questionnaires for 12 months or until reported pregnancy.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Overall, 10 475 participants contributed 38 629 menstrual cycles and 6554 pregnancies during a maximum of 12 cycles of follow-up. We used proportional probabilities regression models to estimate fecundability ratios (FRs) and 95% CIs.

MAIN RESULTS AND THE ROLE OF CHANCE

Compared with upper tertiary education (highest level), fecundability was substantially lower for primary and secondary school (FR: 0.73, 95% CI: 0.62-0.85), upper secondary school (FR: 0.89, 95% CI: 0.79-1.00), vocational education (FR: 0.81, 95% CI: 0.75-0.89), and lower tertiary education (FR: 0.87, 95% CI: 0.80-0.95), but not for middle tertiary education (FR: 0.98, 95% CI: 0.93-1.03). Compared with a monthly household income of >65 000 DKK, fecundability was lower for household income <25 000 DKK (FR: 0.78, 95% CI: 0.72-0.85), 25 000-39 000 DKK (FR: 0.88, 95% CI: 0.82-0.94), and 40 000-65 000 DKK (FR: 0.94, 95% CI: 0.88-0.99). The results did not change appreciably after adjustment for potential confounders.

LIMITATIONS, REASONS FOR CAUTION

We used educational attainment and household income as indicators of SES. However, SES is a complex concept, and these indicators may not reflect all aspects of SES. The study recruited couples planning to conceive, including the full spectrum of fertility from less fertile to highly fertile individuals. Our results may generalize to most couples who are trying to conceive.

WIDER IMPLICATIONS OF THE FINDINGS

Our results are consistent with the literature indicating well-documented inequities in health across socioeconomic groups. The associations for income were surprisingly strong considering the Danish welfare state. These results indicate that the redistributive welfare system in Denmark does not suffice to eradicate inequities in reproductive health.

STUDY FUNDING/COMPETING INTEREST(S)

The study was supported by the Department of Clinical Epidemiology, Aarhus University and Aarhus University Hospital, and the National Institute of Child Health and Human Development (RO1-HD086742, R21-HD050264, and R01-HD060680). The authors declare no conflict of interest.

TRIAL REGISTRATION NUMBER

N/A.

Paraben exposure and couple fecundity: a preconception cohort study

STUDY QUESTION

Is pre-conception exposure to parabens associated with fecundity in couples of childbearing age?

SUMMARY ANSWER

Paraben exposure in female partners was associated with reduced couple fecundity and anti-Müllerian hormone (AMH) might be one of the possible mediators.

WHAT IS KNOWN ALREADY

The reproductive toxicity of parabens, a class of widely used preservatives, has been suggested but evidence regarding their effects on couple fecundity is scarce.

STUDY DESIGN, SIZE, DURATION

In this couple-based prospective cohort study, a total of 884 pre-conception couples who participated in the Shanghai Birth Cohort between 2013 and 2015 were included.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Concentrations of six parabens were measured in urine samples collected from couples. Malondialdehyde, C-reactive protein, and AMH were assessed in female partners. The outcomes included couple fecundability (time-to-pregnancy, TTP) and infertility (TTP > 12 menstrual cycles). Partner-specific and couple-based models were applied to estimate the associations. The joint effect of paraben mixture on couple fecundity was estimated by quantile-based g-computation (q-gcomp). Mediation analysis was used to assess the mediating roles of oxidative stress, inflammation and ovarian reserve.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 525 couples (59.4%) conceived spontaneously. In the partner-specific model, propyl paraben (PrP), butyl paraben (BuP), and heptyl paraben (HeP) in female partners were associated with reduced fecundability (fecundability odds ratio (95% CI): 0.96 (0.94-0.98) for PrP; 0.90 (0.87-0.94) for BuP; 0.42 (0.28-0.65) for HeP) and increased risk of infertility (rate ratio (95% CI): 1.06 (1.03-1.10) for PrP; 1.14 (1.08-1.21) for BuP; 1.89 (1.26-2.83) for HeP). Similar associations were observed in the couple-based model. AMH played a significant mediation role in the association (average causal mediation effect (95% CI): 0.001 (0.0001-0.003)). Paraben exposure in male partners was not associated with couple fecundity. The joint effect of paraben mixture on couple fecundity was non-significant.

LIMITATIONS, REASONS FOR CAUTION

Self-reported pregnancy and single urine sample may lead to misclassification. The mediation analysis is limited in that levels of sex hormones were not measured. The inclusion of women with irregular menstrual cycles might affect the results. It is possible that the observed association was due to reverse causation.

WIDER IMPLICATIONS OF THE FINDINGS

This is the first study to assess the effects of paraben exposure on couple fecundity in Asians. Given the widespread exposure to parabens in couples of childbearing age, the present findings may have important public health implications.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported in part by the National Natural Science Foundation of China (41991314), the Shanghai Science and Technology Development Foundation (22YF1426700), the Science and Technology Commission of Shanghai Municipality (21410713500), and the Shanghai Municipal Health Commission (2020CXJQ01). All authors declare no conflict of interest.

TRIAL REGISTRATION NUMBER

N/A.

Dietary Supplement Intake and Fecundability in a Singapore Preconception Cohort Study

Subfertility is a global problem affecting millions worldwide, with declining total fertility rates. Preconception dietary supplementation may improve fecundability, but the magnitude of impact remains unclear. This prospective cohort study aimed to examine the association of preconception micronutrient supplements with fecundability, measured by time to pregnancy (TTP). The study was conducted at KK Women's and Children's Hospital, Singapore, between February 2015 and October 2017, on 908 women aged 18-45 years old, who were trying to conceive and were enrolled in the Singapore PREconception Study of long-Term maternal and child Outcomes (S-PRESTO). Baseline sociodemographic characteristics and supplement intake were collected through face-to-face interviews. The fecundability ratio (FR) was estimated using discrete-time proportional hazard modelling. Adjusting for potentially confounding variables, folic acid (FA) (FR 1.26, 95% confidence interval 1.03-1.56) and iodine (1.28, 1.00-1.65) supplement users had higher fecundability compared to non-users. Conversely, evening primrose oil supplement users had lower fecundability (0.56, 0.31-0.99) than non-users. In this study, preconception FA and iodine supplementation were associated with shortened TTP, while evening primrose oil use was associated with longer TTP. Nonetheless, the association between supplement use and the magnitude of fecundability changes will need to be further confirmed with well-designed randomised controlled trials.

Association Between Neighborhood Disadvantage and Fertility Among Pregnancy Planners in the US

IMPORTANCE

Decades of inequitable policies in the US have yielded disparities in neighborhood quality, and some studies show that living in a socioeconomically disadvantaged neighborhood is associated with worse health outcomes, including reproductive health outcomes. However, no US studies to date have directly examined the association between residence in disadvantaged neighborhoods and fertility.

OBJECTIVE

To examine the association between residence in disadvantaged neighborhoods and fecundability, a sensitive marker of fertility with many health implications.

DESIGN, SETTING, AND PARTICIPANTS

This prospective preconception cohort study used the Pregnancy Study Online, for which baseline data were collected from June 19, 2013, through April 12, 2019. The study included 6356 participants who identified as female, were 21 to 45 years of age, were attempting conception without fertility treatment, and provided a valid residential address in the contiguous US at enrollment.

EXPOSURES

A standardized area deprivation index (ADI) derived at the census block group level applied to each residential address.

MAIN OUTCOMES AND MEASURES

Fecundability, the per-cycle probability of conception, via questionnaires that were completed every 8 weeks for 12 months, until conception or a censoring event. Proportional probabilities models were used to estimate fecundability ratios and 95% CIs for associations between ADI and fecundability. Restricted cubic splines were also implemented to examine nonlinearity. Models were adjusted for demographic characteristics and factors associated with fertility. The study's a priori hypothesis was that higher levels of neighborhood disadvantage would be associated with decreased fecundability.

RESULTS

Among 6356 participants, 3725 pregnancies were observed for 27 427 menstrual cycles of follow-up. The mean (SD) baseline age was 30.0 (4.1) years, and most participants were non-Hispanic White (5297 [83.3%]) and nulliparous (4179 [65.7%]). Comparing the top and bottom deciles of disadvantaged neighborhood status, adjusted fecundability ratios were 0.79 (95% CI, 0.66-0.96) for national-level ADI rankings and 0.77 (95% CI, 0.65-0.92) for within-state ADI rankings. Restricted cubic splines showed some evidence of nonlinearity in the association. Associations were slightly stronger among participants with lower annual incomes (<$50 000).

CONCLUSIONS AND RELEVANCE

In this cohort study, residence in a socioeconomically disadvantaged neighborhood was associated with moderately decreased fecundability. If confirmed in other studies, these results suggest that investments to reduce disadvantaged neighborhood status may yield positive cobenefits for fertility.