Do vaccines affect fertility or pregnancy?
Here is what the checked sources say. Each title links to the original.
A Prospective Cohort Study of COVID-19 Vaccination, SARS-CoV-2 Infection, and Fertility
Followed 2,126 women aged 21 to 45 in the US and Canada (enrolled December 2020 to September 2021), and their partners, while they tried to conceive without fertility treatment. COVID-19 vaccination in either partner was not appreciably associated with the chance of conceiving per cycle (women: ratio 1.08, 95% CI 0.95 to 1.23; men: 0.95, 0.83 to 1.10). Male COVID-19 infection within the previous 60 days was linked to a possible short-term dip in fertility. The study covers COVID-19 vaccines only.
Systematic review and meta-analysis of the effectiveness and perinatal outcomes of COVID-19 vaccination in pregnancy
Pooled 23 studies covering 117,552 vaccinated pregnant people, nearly all with mRNA COVID-19 vaccines. It found no evidence of higher risk of miscarriage, preterm birth, placental abruption, postpartum bleeding, maternal death, intensive care admission, lower birthweight or newborn intensive care admission. Stillbirth was 15% less likely among vaccinated people, an association. In the studies reviewed (published 2022), two doses were 89.5% effective against confirmed infection from 7 days after the second dose. One author led Pfizer's COVID-19 vaccine trial in pregnancy.
Effectiveness and safety of COVID-19 vaccines on maternal and perinatal outcomes: a systematic review and meta-analysis
A WHO-linked review of 67 studies (searches to January 2023) covering about 1.8 million women. Overall, COVID-19 vaccination during pregnancy was not associated with increased risk of adverse pregnancy or newborn outcomes. In test-negative studies, fully vaccinated women had 61% lower odds of infection in pregnancy and 94% lower odds of hospital admission for it, estimates for that study period. Cohort studies found slightly fewer high-blood-pressure disorders and caesareans, and babies 8% less likely to need neonatal intensive care. Injection-site pain was the most common side effect.
Vaccinations in pregnancy
The UK NHS page for pregnant women (last reviewed January 2023) recommends the inactivated flu vaccine and the whooping cough vaccine in pregnancy. Pregnant women are more likely to have flu complications, and whooping cough antibodies pass to the baby, protecting it until its own shots at 8 weeks. The NHS offers RSV vaccine from around 28 weeks to protect the baby for its first 6 months. Live vaccines such as MMR are usually delayed until after birth because of a potential risk of infecting the baby, though the NHS says there's no evidence any causes birth defects.
Safety of pertussis vaccination in pregnant women in UK: observational study
The UK medicines regulator studied 20,074 pregnant women given whooping cough (pertussis) vaccine, mostly in the third trimester, using GP records. Stillbirth was not detectably more common in the 14 days after vaccination (rate ratio 0.69, 95% CI 0.23 to 1.62) or later in pregnancy (0.85) than historical national rates. Against a matched historical unvaccinated group, no increase was found in maternal or newborn death, pre-eclampsia, bleeding, caesarean delivery or low birth weight. The authors limit their conclusion to third-trimester vaccination and call these early data.