UPDATE: Is it Safe to get the Covid Vaccine if I’m Pregnant or Thinking of Becoming Pregnant?

There have been some substantial updates, all good news, to this question since the original article written on this topic in early February.

Last Friday, commenting on a recently published article on the topic in the New England Journal of Medicine (NEJM), CDC Director Rochelle Walensky said during a White House press briefing that the “CDC recommends that pregnant people receive the COVID-19 vaccine.”  She walked that back on Tuesday, stating the agency’s stance has not changed from last month.  The CDC’s March guidance she was referring to was less strong than a full-on recommendation, instead stating, “If you are pregnant, you may choose to receive a COVID-19 vaccine, and “you may want to have a conversation with your healthcare provider.”  The guidance adds, “Based on how these vaccines work in the body, experts believe they are unlikely to pose a specific risk for people who are pregnant. However, there are currently limited data on the safety of COVID-19 vaccines in pregnant people.”

The NEJM article Walensky was discussing, published on April 21, 2021, reviewed data from December 14,2020 to February 28, 2021 from the v-safe after vaccination health checker surveillance system, the v-safe pregnancy registry, and the Vaccine Adverse Event Reporting System (VAERS) to characterize the initial safety of mRNA COVID-19 vaccines in pregnancy.  A total of 36,000 v-safe participants aged 16 to 54 years of age identified as pregnant.  Among 4000 participants enrolled in the pregnancy registry, 830 had completed a pregnancy.  Calculated proportions of adverse pregnancy and neonatal outcomes in persons vaccinated who had completed a pregnancy were similar to incidences reported in studies involving pregnant women that were conducted before the pandemic.  Preliminary findings did not show obvious safety signals among pregnant persons who received mRNA COVID-19 vaccines.  However, the authors state, “more longitudinal follow-up, including follow-up of large numbers of women vaccinated earlier in pregnancy, is necessary to inform maternal, pregnancy and infant outcomes.”

A study published in March in the American Journal of Obstetrics and Gynecology by researchers at Massachusetts General Hospital (MGH), Brigham and Women’s Hospital, MIT and Harvard looked at 131 women of reproductive age (84 pregnant, 31 lactating and 16 non-pregnant), all of whom received one of the two new mRNA vaccines: Pfizer-BioNTech or Moderna.  The study found the mRNA COVID-19 vaccines to be highly effective in producing vaccine-induced antibody titers in pregnant and lactating women, with titer levels similar to those of non-pregnant women. All vaccine-generated titers were higher than those generated by SARS-CoV-2 infection during pregnancy, suggesting immunity from vaccination is stronger than that from natural infection, something we’re seeing in many studies.  Immune transfer to neonates was seen to occur via placenta and breastmilk, corresponding to similar findings in other recent studies demonstrating evidence of immune protection of infants through their mothers’ vaccinations.  

While both safety and efficacy evidence continues to mount, most current official recommendations still stop short of a direct recommendation that pregnant women receive the vaccine.  As evidence continues to increase and we begin to see some longer-term data on infant outcomes months after birth, we hope we continue to see promising results to provide further reassurance to pregnant and lactating women.

Jennifer Abrams, MD, April 28, 2021