Early data indicate Pfizer, Moderna vaccines safe for pregnant women

The Pfizer-BioNTech and Moderna vaccines appear to be safe for pregnant women after an early analysis of COVID-19 vaccine data found no evidence of serious risks. 

The study, published in The New England Journal of Medicine on Wednesday, examined data from the first 11 weeks of the U.S.’s vaccination effort, when only the two messenger RNA vaccines had emergency use authorization in the country. 

Researchers at the Centers for Disease Control and Prevention (CDC) studied responses from more than 35,000 women who reported getting one of the shots during or shortly before pregnancy in between Dec. 14 and Feb. 28. The analysis represents the largest study on the safety of the vaccine for pregnant women so far, as pregnant women were not included in the clinical trials for the shots.  

According to the analysis, pregnant women experienced the same side effects as nonpregnant people, with reporting injection-site pain and nausea and vomiting more frequently after their second dose. But pregnant women were found to report headache, chills and fever less often. 

The women ranged from 16 to 54 years old, with most being between 25 to 34, and self-reported their information using the CDC’s safety monitoring system V-safe. Those who said they were pregnant on V-safe were invited to participate in the V-safe pregnancy registry, which collected more data.

The registry found 827 women completed their pregnancy with 86 percent resulting in a live birth, while the rates of miscarriage and prematurity aligned with the nonvaccinated population. 

A total of 28.6 percent were vaccinated during the first trimester, 43.3 percent during the second trimester and 25.7 percent during the third trimester, as well as 2.3 percent during preconception. 

The study comes after health officials, including at the CDC, and experts have advised that the COVID-19 vaccine be available to pregnant women and that these women talk to their doctors about deciding whether to get vaccinated. 

Pregnant women have been found to be more at risk of getting seriously ill or dying from COVID-19 than nonpregnant women with symptoms. 

The researchers said more data is needed due to the voluntary nature of the reporting system. A wide majority of 94 percent of pregnant women who reported their data were considered health care personnel, as the profession was prioritized for vaccines in the early weeks of the rollout.