COVID-19 vaccines do not affect fertility or early pregnancy, study of IVF patients confirms

A new study involving in vitro fertilization patients in the U.S. found that those who received Pfizer or Moderna COVID-19 vaccines had the same fertility and pregnancy outcomes as unvaccinated patients – findings that researchers say provide further evidence that mRNA vaccines are safe for those considering pregnancy.

The study, published Tuesday in the journal Obstetrics & Gynecology, noted that while data on vaccine safety in pregnancy is increasing, vaccination rates amongst pregnant people remain low.

Previous studies have found no associations with COVID-19 mRNA vaccines with markers of fertility, including embryo development, but were from smaller cohorts.

Researchers analyzed data collected from nearly 3,000 patients who underwent IVF at a single academic centre.

One cohort was fully vaccinated with two doses of the Pfizer or Moderna vaccine 14 days or more before the start of their medications associated with IVF, and there was a control group of unvaccinated patients undergoing the same IVF procedures and taking the same medications during the same time period.

Both cohorts of patients had ultrasounds and weekly monitoring to determine whether a pregnancy had resulted from the IVF treatment, as well as screening for COVID-19.

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The study found no differences between the vaccinated and unvaccinated cohorts of patients in all categories of measuring successful IVF implantation and early pregnancy.

The study took into account age, body mass index, hormone levels, gravidity (sum of all pregnancies in an individual, including live births and pregnancies that terminated at less than six months or did not result in a live birth), parity (pregnancies that resulted in delivery at more than six months gestation, either a live birth or still birth) and stimulation (second-stage IVF treatment to harvest mature eggs) type.

“Our data contribute to the ever-increasing evidence that COVID-19 vaccines to not negatively affect fertility or pregnancy,” the researchers wrote.