Large Study Provides Reassurance That COVID-19 Vaccination Does Not Affect Fertility or Early Pregnancy

Vaccination against COVID-19 did not affect fertility outcomes in patients undergoing in-vitro fertilization (IVF), according to a study by investigators at the Icahn School of Medicine at Mount Sinai and Reproductive Medicine Associates of New York (RMA of New York). The findings, which were published in January 2022 in Obstetrics & Gynecology (the Green Journal), add to the growing body of evidence providing reassurance that COVID-19 vaccination does not affect fertility.

The study compared rates of fertilization, pregnancy, and early miscarriage in IVF patients who had received two doses of vaccines manufactured by Pfizer or Moderna with the same outcomes in nonvaccinated patients. The two groups of patients who underwent frozen-thawed embryo transfer—214 vaccinated and 733 unvaccinated—had similar rates of pregnancy and early pregnancy loss. The two groups of patients who underwent ovarian stimulation—222 vaccinated and 983 unvaccinated—had similar rates of eggs retrieved, fertilization, and embryos with normal numbers of chromosomes, among several other measures.

“This is one of the largest studies to review fertility and IVF cycle outcomes in patients who received COVID-19 vaccinations. The study found no significant differences in response to ovarian stimulation, egg quality, embryo development, or pregnancy outcomes between the vaccinated compared to unvaccinated patients,” said Devora A. Aharon, MD, first author of the study. Dr. Aharon is a fellow in reproductive endocrinology and infertility at Icahn Mount Sinai and RMA of New York. “Our findings that vaccination had no impact on these outcomes should be reassuring to those who are trying to conceive or are in early pregnancy.”

The retrospective study included patients who underwent controlled ovarian hyperstimulation or single euploid frozen-thawed embryo transfer at RMA of New York between February and September 2021. Data were collected as part of routine clinical practice and extracted from the electronic medical record.

Controlled ovarian hyperstimulation cycles and frozen-thawed embryo transfer cycles were assessed separately as independent cohorts. The study groups for the controlled ovarian hyperstimulation and frozen-thawed embryo transfer cohorts consisted of fully vaccinated patients, defined as patients who received two doses of the Pfizer-BioNTech or Moderna COVID-19 vaccine 14 days or more before the start of medications for their controlled ovarian hyperstimulation or frozen-thawed embryo transfer cycle. The control groups consisted of unvaccinated patients undergoing controlled ovarian hyper stimulation or frozen-thawed embryo transfer during the same time period.

The primary outcome of fertilization rate for the controlled ovarian hyperstimulation cohort was similar between the vaccinated and unvaccinated groups—80.7 percent vs 78.7 percent. No differences were observed between vaccinated and unvaccinated patients on univariate and multivariate analysis in the secondary outcomes of eggs retrieved, mature oocytes retrieved, mature oocytes ratio, or blastulation rate.

The primary outcome of clinical pregnancy rate in the frozen-thawed embryo transfer cohort was similar between the vaccinated and unvaccinated groups—59.5 percent vs 63.7 percent. No significant differences were seen between vaccinated and unvaccinated patients on univariate and multivariate analysis in the secondary outcomes of pregnancy rate, ongoing pregnancy rate, biochemical loss rate, or clinical pregnancy loss rate.

The authors of the study anticipate that the findings will ease the anxiety of people considering pregnancy. “By leveraging science and big data, we can help reassure patients of reproductive age and enable them to make the best decisions for themselves. It will give people comfort to know that the COVID-19 vaccine does not affect their reproductive potential,” said senior author Alan B. Copperman, MD, FACOG, division director and Clinical Professor of Obstetrics, Gynecology and Reproductive Science at Icahn Mount Sinai and Director of RMA of New York, which is recognized internationally as a leading center of reproductive medicine.

The publication of the study coincided with the surge of the highly contagious Omicron variant. Previous studies have found that COVID-19 vaccination helped protect pregnant people—for whom COVID-19 substantially increases the risk of severe illness and death—from severe illness, conferred antibodies to their infants, and did not raise the risk of preterm birth or fetal growth problems.