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Introduction Per- and polyfluoroalkyl substances (PFAS) are environmentally persistent synthetic chemicals found in consumer products, firefighting foam, and contaminated food and water. (1) Routes of exposure include ingestion, inhalation, and [...]

Background: On June 24th, 2022, the United States (US) Supreme Court's ruling in Dobbs v. Jackson, et al. (hereafter, the Dobbs decision) removed federal‐level protections for induced abortion, sparking concerns about reproductive rights and health privacy. Although other pregnancy outcomes (e.g. spontaneous abortion, ectopic pregnancy) are not explicit targets of post‐Dobbs abortion bans, study participants may be worried about how their reproductive health data are used by researchers in the post‐Dobbs era. Objective: To evaluate the extent to which the Dobbs decision influenced participant's engagement in a preconception cohort study. Methods: We leveraged data spanning 20 weeks before and after the Dobbs decision (4 February 2022, to 11 November 2022) from US participants in Pregnancy Study Online (PRESTO), an internet‐based prospective preconception cohort study of couples attempting conception. We categorised participants' state‐level abortion access by residential location: banned or restricted rights; limited access; and protected rights. We evaluated three participant engagement outcomes: follow‐up questionnaire completion; report of a pregnancy; and clicking on the invitation link for a fertility‐tracking app. We fit separate linear regression models and restricted cubic splines to compare outcome prevalence before and after the Dobbs decision by state‐level abortion category. Results: A total of 585 newly enrolled participants and 1247 already‐enrolled participants received 2802 invitations to complete a follow‐up questionnaire. In states with limited or protected abortion rights, we observed little change in participant engagement. In states with banned or restricted abortion rights, however, we observed a 27.12 percentage point reduction (95% confidence interval −43.68, −10.51) in the prevalence of clicking on the invitation link for the fertility‐tracking app comparing the post‐ versus pre‐Dobbs periods. Conclusions: There was some evidence of reduced participant engagement after the Dobbs decision in states with banned or restricted abortion rights, indicating potentially deleterious effects on the conduct of reproductive health studies. [ABSTRACT FROM AUTHOR]

STUDY QUESTION To what extent is preconception maternal or paternal coronavirus disease 2019 (COVID-19) vaccination associated with miscarriage incidence? SUMMARY ANSWER COVID-19 vaccination in either partner at any time before conception is not associated with an increased rate of miscarriage. WHAT IS KNOWN ALREADY Several observational studies have evaluated the safety of COVID-19 vaccination during pregnancy and found no association with miscarriage, though no study prospectively evaluated the risk of early miscarriage (gestational weeks [GW] <8) in relation to COVID-19 vaccination. Moreover, no study has evaluated the role of preconception vaccination in both male and female partners. STUDY DESIGN, SIZE, DURATION An Internet-based, prospective preconception cohort study of couples residing in the USA and Canada. We analyzed data from 1815 female participants who conceived during December 2020–November 2022, including 1570 couples with data on male partner vaccination. PARTICIPANTS/MATERIALS, SETTING, METHODS Eligible female participants were aged 21–45 years and were trying to conceive without use of fertility treatment at enrollment. Female participants completed questionnaires at baseline, every 8 weeks until pregnancy, and during early and late pregnancy; they could also invite their male partners to complete a baseline questionnaire. We collected data on COVID-19 vaccination (brand and date of doses), history of SARS-CoV-2 infection (yes/no and date of positive test), potential confounders (demographic, reproductive, and lifestyle characteristics), and pregnancy status on all questionnaires. Vaccination status was categorized as never (0 doses before conception), ever (≥1 dose before conception), having a full primary sequence before conception, and completing the full primary sequence ≤3 months before conception. These categories were not mutually exclusive. Participants were followed up from their first positive pregnancy test until miscarriage or a censoring event (induced abortion, ectopic pregnancy, loss to follow-up, 20 weeks' gestation), whichever occurred first. We estimated incidence rate ratios (IRRs) for miscarriage and corresponding 95% CIs using Cox proportional hazards models with GW as the time scale. We used propensity score fine stratification weights to adjust for confounding. MAIN RESULTS AND THE ROLE OF CHANCE Among 1815 eligible female participants, 75% had received at least one dose of a COVID-19 vaccine by the time of conception. Almost one-quarter of pregnancies resulted in miscarriage, and 75% of miscarriages occurred <8 weeks' gestation. The propensity score-weighted IRR comparing female participants who received at least one dose any time before conception versus those who had not been vaccinated was 0.85 (95% CI: 0.63, 1.14). COVID-19 vaccination was not associated with increased risk of either early miscarriage (GW: <8) or late miscarriage (GW: 8–19). There was no indication of an increased risk of miscarriage associated with male partner vaccination (IRR = 0.90; 95% CI: 0.56, 1.44). LIMITATIONS, REASONS FOR CAUTION The present study relied on self-reported vaccination status and infection history. Thus, there may be some non-differential misclassification of exposure status. While misclassification of miscarriage is also possible, the preconception cohort design and high prevalence of home pregnancy testing in this cohort reduced the potential for under-ascertainment of miscarriage. As in all observational studies, residual or unmeasured confounding is possible. WIDER IMPLICATIONS OF THE FINDINGS This is the first study to evaluate prospectively the relation between preconception COVID-19 vaccination in both partners and miscarriage, with more complete ascertainment of early miscarriages than earlier studies of vaccination. The findings are informative for individuals planning a pregnancy and their healthcare providers. STUDY FUNDING/COMPETING INTEREST(S) This work was supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development, the National Institute of Health [R01-HD086742 (PI: L.A.W.); R01-HD105863S1 (PI: L.A.W. and M.L.E.)], the National Institute of Allergy and Infectious Diseases (R03-AI154544; PI: A.K.R.), and the National Science Foundation (NSF-1914792; PI: L.A.W.). The funders had no role in the study design, data collection, analysis and interpretation of data, writing of the report, or the decision to submit the paper for publication. L.A.W. is a fibroid consultant for AbbVie, Inc. She also receives in-kind donations from Swiss Precision Diagnostics (Clearblue home pregnancy tests) and Kindara.com (fertility apps). M.L.E. received consulting fees from Ro, Hannah, Dadi, VSeat, and Underdog, holds stock in Ro, Hannah, Dadi, and Underdog, is a past president of SSMR, and is a board member of SMRU. K.F.H. reports being an investigator on grants to her institution from UCB and Takeda, unrelated to this study. S.H.-D. reports being an investigator on grants to her institution from Takeda, unrelated to this study, and a methods consultant for UCB and Roche for unrelated drugs. The authors report no other relationships or activities that could appear to have influenced the submitted work. TRIAL REGISTRATION NUMBER N/A. [ABSTRACT FROM AUTHOR]

Background: Many reproductive‐aged North Americans use antibiotics in the weeks preceding conception or during early pregnancy. Antibiotic use may influence risk of spontaneous abortion (SAB) by disrupting the reproductive tract microbiome or treating harmful infections. However, this association has not been extensively studied. Objective: To determine the extent to which periconceptional antibiotic use is associated with the risk of SAB. Methods: We analysed data from an internet‐based preconception cohort study of pregnancy planners. Eligible participants self‐identified as female, were aged 21–45 years, resided in the USA or Canada, and conceived during 12 months of follow‐up (n = 7890). Participants completed an enrolment questionnaire during June 2013–September 2021 and bimonthly follow‐up questionnaires for up to 12 months or until a reported pregnancy, whichever came first. Pregnant participants completed questionnaires in early (~8–9 weeks) and late (~32 weeks) gestation. We assessed antibiotic use, including type (penicillins, nitrofurantoin, cephalosporins and macrolides) and indication for use, during the previous 4 weeks on preconception questionnaires. Participants reported pregnancies and SAB on follow‐up and pregnancy questionnaires. We used Cox proportional hazards regression models with gestational weeks as the time scale to estimate hazard ratios (HR) and 95% confidence intervals (CI) for the association between periconceptional antibiotic use and SAB, controlling for potential demographic, medical, and lifestyle confounders. Results: Nineteen percent (n = 1537) of pregnancies ended in SAB. Participants reported periconceptional antibiotic use in 8% of pregnancies ending in SAB and 7% not ending in SAB. Periconceptional antibiotic use was not appreciably associated with SAB (adjusted HR 1.06, 95% CI 0.88, 1.28). We observed no strong associations between antibiotic type, indication for use, or recency of exposure and SAB risk. Conclusions: Periconceptional antibiotic use was not appreciably associated with SAB in this study. This association is likely complicated by antibiotic type and dosage, timing of conception, and the individual's overall health. [ABSTRACT FROM AUTHOR]

Background: Psychological stress is prevalent among reproductive‐aged men. Assessment of semen quality for epidemiological studies is challenging as data collection is expensive and cumbersome, and studies evaluating the effect of perceived stress on semen quality are inconsistent. Objective: To examine the association between perceived stress and semen quality. Material and methods: We analyzed baseline data on 644 men (1,159 semen samples) from two prospective preconception cohort studies during 2015–2021: 592 in Pregnancy Study Online (PRESTO) and 52 in SnartForaeldre.dk (SF). At study entry, men aged ≥21 years (PRESTO) and ≥18 years (SF) trying to conceive without fertility treatment completed a questionnaire on reproductive and medical history, socio‐demographics, lifestyle, and the 10‐item version of the Perceived Stress Scale (PSS; interquartile range [IQR] of scores: 0–40). After enrollment (median weeks: 2.1, IQR: 1.3–3.7), men were invited to perform in‐home semen testing, twice with 7–10 days between tests, using the Trak Male Fertility Testing System. Semen quality was characterized by semen volume, sperm concentration, and total sperm count. We fit generalized estimating equation linear regression models to estimate the percent difference in mean log‐transformed semen parameters by four PSS groups (<10, 10–14, 15–19, ≥20), adjusting for potential confounders. Results: The median PSS score and IQR was 15 (10–19), and 136 men (21.1%) had a PSS score ≥20. Comparing men with PSS scores ≥20 with <10, the adjusted percent difference was −2.7 (95% CI: −9.8; 5.0) for semen volume, 6.8 (95% CI: ‐10.9; 28.1) for sperm concentration, and 4.3 (95% CI: −13.8; 26.2) for total sperm count. Conclusion: Our findings indicate that perceived stress is not materially associated with semen volume, sperm concentration, or total sperm count. [ABSTRACT FROM AUTHOR]

Some reproductive-aged individuals remain unvaccinated against coronavirus disease 2019 (COVID-19) because of concerns about potential adverse effects on fertility. Using data from an internet-based preconception cohort study, we examined the associations of COVID-19 vaccination and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection with fertility among couples trying to conceive spontaneously. We enrolled 2,126 self-identified female participants aged 21–45 year residing in the United States or Canada during December 2020–September 2021 and followed them through November 2021. Participants completed questionnaires every 8 weeks on sociodemographics, lifestyle, medical factors, and partner information. We fit proportional probabilities regression models to estimate associations between self-reported COVID-19 vaccination and SARS-CoV-2 infection in both partners with fecundability (i.e. the per-cycle probability of conception), adjusting for potential confounders. COVID-19 vaccination was not appreciably associated with fecundability in either partner (female fecundability ratio (FR) = 1.08, 95% confidence interval (CI): 0.95, 1.23; male FR = 0.95, 95% CI: 0.83, 1.10). Female SARS-CoV-2 infection was not strongly associated with fecundability (FR = 1.07, 95% CI: 0.87, 1.31). Male infection was associated with a transient reduction in fecundability (for infection within 60 days, FR = 0.82, 95% CI: 0.47, 1.45; for infection after 60 days, FR = 1.16, 95% CI: 0.92, 1.47). These findings indicate that male SARS-CoV-2 infection may be associated with a short-term decline in fertility and that COVID-19 vaccination does not impair fertility in either partner. [ABSTRACT FROM AUTHOR]

Background: Animal and epidemiologic studies indicate that air pollution may adversely affect fertility. Epidemiologic studies have been restricted largely to couples undergoing fertility treatment or have retrospectively ascertained time-to-pregnancy among pregnant women.Objectives: We examined the association between residential ambient air pollution and fecundability, the per-cycle probability of conception, in a large preconception cohort of Danish pregnancy planners.Methods: During 2007-2018, we used the Internet to recruit and follow women who were trying to conceive without the use of fertility treatment. Participants completed an online baseline questionnaire eliciting socio-demographic characteristics, lifestyle factors, and medical and reproductive histories and follow-up questionnaires every 8 weeks to ascertain pregnancy status. We determined concentrations of ambient nitrogen oxides (NOx ), nitrogen dioxide (NO2 ), carbon monoxide (CO), ozone (O3 ), particulate matter <2.5 µm (PM2.5 ) and <10 µm (PM10 ), and sulphur dioxide (SO2 ) at each participant's residential address. We calculated average exposure during the year before baseline, during each menstrual cycle over follow-up and during the entire pregnancy attempt time. We used proportional probabilities regression models to estimate fecundability ratios (FRs) and 95% confidence intervals (CIs), adjusting for potential confounders and co-pollutants. The analysis was restricted to the 10,183 participants who were trying to conceive for <12 cycles at study entry whose addresses could be geocoded.Results: During 12 months of follow-up, 73% of participants conceived. Higher concentrations of PM2.5 and PM10 were associated with small reductions in fecundability. For example, the FRs for a one interquartile range (IQR) increase in PM2.5 (IQR = 3.2 µg/m3 ) and PM10 (IQR = 5.3 µg/m3 ) during each menstrual cycle were 0.93 (95% CI: 0.87, 0.99) and 0.91 (95% CI: 0.84, 0.99), respectively. Other air pollutants were not appreciably associated with fecundability.Conclusions: In this preconception cohort study of Danish women, residential exposures to PM2.5 and PM10 were associated with reduced fecundability. [ABSTRACT FROM AUTHOR]

Background: Semen quality assessment in population-based epidemiologic studies presents logistical and financial challenges due to reliance on centralised laboratory semen analysis. The Trak Male Fertility Testing System is an FDA-cleared and validated at-home test for sperm concentration and semen volume, with a research use only sperm motility test. Here we evaluate the Trak System's overall utility among men participating in Pregnancy Study Online (PRESTO), a web-based study of North American couples planning pregnancy.Methods: US male participants aged ≥21 years with ≤6 months of pregnancy attempt time at study enrolment were invited to participate in the semen testing substudy after completing their baseline questionnaire. Consenting participants received a Trak Engine (battery-powered centrifuge) and two test kits. Participants shared their test results via smartphone images uploaded to online questionnaires. Data were then linked with covariate data from the baseline questionnaire.Results: Of the 688 men invited to participate, 373 (54%) provided consent and 271 (73%) completed at least one semen test result. The distributions of semen volume, sperm concentration, motile sperm concentration, total sperm count, and total motile sperm count were similar to 2010 World Health Organization (WHO) semen parameter data of men in the general population. The overall usability score for the Trak System was 1.4 on a 5-point Likert scale (1 = Very Easy, 5 = Difficult), and 92% of participants believed they performed the test correctly and received an accurate result. Lastly, men with higher motile sperm count were more likely to report feeling "at ease" or "excited" following testing, while men with low motile sperm count were more likely to report feeling "concerned" or "frustrated." Overall, 91% of men reported they would like to test again.Conclusions: The Trak System provides a simple and potentially cost-effective means of measuring important semen parameters and may be useful in population-based epidemiologic fertility studies. [ABSTRACT FROM AUTHOR]

Background Objective Methods Results Conclusion 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 ≥ 25 kg/m2.Greater SSB consumption was associated with reduced semen quality in a North American preconception cohort. [ABSTRACT FROM AUTHOR]

Food frequency questionnaires require updating over time, due to population changes in diet, posing analytical challenges in consistently measuring diet in prospective studies. We compared reliability and agreement between nutrients in two versions of the National Cancer Institute's web-based Diet History Questionnaire (DHQ, III vs. II) in an ongoing North American preconception study. We invited 51 consecutively-enrolled U.S. female participants aged 21-45 years to complete both DHQ versions within a 2-week period, in a randomized order. We compared 30 nutrients from both DHQ versions and calculated within-person reliability using intraclass correlation coefficients (ICCs). Bland-Altman plots and 95% limits of agreement (LOA) were generated to assess nutrient agreement between DHQ versions. We observed highest reliability in percent energy from carbohydrates and cholesterol (ICCs: 0.88; 95% CI: 0.80-0.93) and lowest for percent energy from protein and vitamin D (ICCs: 0.56; 95% CI: 0.34-0.72). At the group level, all nutrients had most observations within the LOA. Bland-Altman plots showed assessment differences between DHQs for protein, fat, monounsaturated fat, and vitamin D. The remaining nutrients showed good agreement and good-to-moderate reliability. Some nutrients may require adjustment and calibration analysis before using them interchangeably across DHQ versions., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)