A new study published in Human Reproduction shows no evidence that COVID-19 vaccination in either male or female partners is linked to early or late miscarriages and that maternal vaccination shortly before conception has no impact on early (less than 8 weeks) miscarriage rates.
The study was based on outcomes seen in the Boston University School of Public Health’s Pregnancy Study Online (PRESTO), an ongoing study that follows participants from preconception through 6 months after delivery. The present study included 1,815 women from the United States and Canada who were followed from December 2020 through November 2022. The women were ages 21 to 45 years and were trying to conceive without the use of fertility treatment at enrollment.
Questionnaires were administered at enrollment and every 8 weeks thereafter and asked about general health, gestational health, COVID-19 infections, and COVID-19 vaccinations. Of all participants, 75% had received at least one dose of a COVID-19 vaccine by the time of conception.
Vaccinated women had slightly lower miscarriage rates
Overall, 446 (24.6%) participants experienced a miscarriage. The risk of miscarriage was 26.6% among unvaccinated women, 23.9% among women who had received more than one dose before conception, 24.5% among those who completed a full primary sequence before conception, and 22.1% among those who completed the sequence at or less than 3 months before conception.
No effect was seen on male vaccination status and miscarriage rates. The study adds to a growing body of literature showing no evidence that COVID-19 vaccines reduce fertility or increase miscarriage risk.
Our data indicated a slightly lower risk of miscarriage among vaccinated individuals.
"The rate of miscarriage among vaccinated individuals was not only comparable with that of PRESTO participants who conceived before the pandemic, but our data indicated a slightly lower risk of miscarriage among vaccinated individuals compared to unvaccinated individuals,” said lead author Jennifer Yland, an epidemiology PhD student at Boston University, in a press release.