There is no evidence that mRNA COVID-19 vaccines cause or are associated with miscarriages, also called spontaneous abortions in cases where unexpected pregnancy loss occurs at less than 20 weeks.

Recent studies have shown that pregnant women who received mRNA COVID-19 vaccines and suffered miscarriages did so at a rate similar to the standard population. In general, miscarriages are relatively common pregnancy outcomes and impact 11-22% of pregnancies.

A study published in April of 2021 in Ultrasound in Obstetrics & Gynecology found that the incidence of miscarriages was increased by 25% during the pandemic in their study population, a higher rate than reported in studies that occurred pre-pandemic.

In one study from the JAMA, researchers looked at data from eight health systems in the United States. The team evaluated information on 105,446 women who were between 6 and 19 weeks into their pregnancies. In all, 7.8% of the women had received and least one Pfizer-BioNTech shot and 6% had received at least one Moderna shot. In total, 13,160 women suffered miscarriages but there was no difference in risk for miscarriages between unvaccinated and vaccinated women (who received shots within the previous 28 days).

There were some limitations to the study but so far, this paper includes one of the largest sample sizes of pregnant women during COVID-19 to date.

Conversely, COVID-19 is linked to a higher risk for severe disease and complications in pregnant women with and without symptoms, including preterm birth, hospitalization, and mortality. One-quarter of all neonates born to mothers with COVID-19 infections were admitted to neonatal intensive care units, a higher risk in women infected with the virus than in women without it.

Evidence currently shows there are no obvious safety issues among pregnant people who received mRNA COVID-19 vaccines but there are significant safety issues among unvaccinated pregnant people who have COVID-19 infections.

In a recent search on the Vaccine Adverse Event Reporting System (VAERS), there were 1,098 spontaneous abortion reports (including 2 incomplete and 1 complete additional reports). However, submissions to the VAERS database can be made by any person and "does not mean that healthcare personnel or the vaccine caused or contributed to the adverse event (possible side effect)."

There is no evidence to suggest that the miscarriages reported to VAERS were accurately represented or associated with mRNA vaccines.

Several social media posts have incorrectly stated that mRNA vaccines have been linked to infertility, negative pregnancy outcomes, and miscarriages. This information has been debunked both by peer-reviewed, evidence-based scientific studies as well as fact-checking organizations.

The risk for pregnant women with COVID-19 - which is significantly reduced among women vaccinated against the virus - for complications is higher than in the general population. Vaccination and prevention strategies continue to be the strongest tools we have in ensuring healthier outcomes for mothers and babies.