A Prospective Cohort Study of COVID-19 Vaccination, SARS-CoV-2 Infection, and Fertility.

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.

Accuracy of self-reported birth outcomes relative to birth certificate data in an Internet-based prospective cohort study.

BACKGROUND: The accuracy of birth outcome data provided by Internet-based cohort study participants has not been well studied. METHODS: We compared self-reported data on birth characteristics in Pregnancy Study Online (PRESTO), an Internet-based prospective cohort study of North American pregnancy planners, with birth certificate data. At enrolment, participants were aged 21-45 years, attempting conception, and not using fertility treatment. Women completed online questionnaires during preconception, early and late pregnancy, and postpartum. We requested birth certificate data during 2014-2019 from seven health departments in states with the most participants. After restricting to singleton births, we assessed specificity, sensitivity, and agreement comparing self-reported data from postpartum questionnaires with birth certificate data for gestational age at delivery (GA) and birthweight (grams). Our primary measure of self-reported GA (weeks) was calculated as [280-(due date-birth date)]/7. We used log-binomial regression to assess predictors of agreement. RESULTS: We linked 85% (771/909) of women in selected states. Median age of women was 30 years (range: 21-42), 84% had ≥ 16 years of education, nearly 96% were married, 12% had household incomes <$50 000, 32% were parous, and 85% identified as non-Hispanic White. Median recall interval was 6 months. Among those with self-reported data, 89% reported the same GA as the birth certificate and 98% reported GA within 1 week of the birth certificate. Self-report of preterm birth (GA < 37 weeks) agreed with information from birth certificates for 100% of women; sensitivity was 100%, and specificity was 99%. Self-reported low birthweight (<2500 grams) agreed with birth certificates for 93% of women; sensitivity and specificity were 93% and ≥99%, respectively. Predictors of poorer agreement included higher parity and longer pregnancy attempt time for GA, and lower education and longer recall interval for birthweight. CONCLUSION: Self-reported data on GA and birthweight from an Internet-based cohort showed high accuracy compared with birth certificates.