A health worker administers a dose of the Pfizer-BioNtech COVID-19 coronavirus vaccine to a pregnant woman at Clalit Health Services, in Israel's Mediterranean coastal city of Tel Aviv on January 23, 2021.
Jack Guez | AFP | Getty Images
The Centers for Disease Control and Prevention is recommending Covid-19 shots for pregnant women after preliminary data from the largest study of coronavirus vaccine use among expectant mothers showed that Pfizer's and Moderna's jabs were safe for the women as well as their babies.
The researchers found no "obvious safety signals" among any of the 35,691 women who were followed in the peer-reviewed study published Wednesday by The New England Journal of Medicine. Data used in the research was self-reported, and the participants' ages ranged from 16 to 54 years old.
"No safety concerns were observed for people vaccinated in the third trimester or safety concerns for their babies," CDC Director Dr. Rochelle Walensky said Friday. "As such, CDC recommends pregnant people receive Covid-19 vaccines."
The researchers used the "v-safe after vaccination health checker" surveillance system, the v-safe pregnancy registry and the Vaccine Adverse Event Reporting System to characterize the initial safety of mRNA Covid-19 vaccines in pregnant women, according to the study.
Pregnant women, versus those who weren't, reported injection-site pain more frequently, but fewer other side effects such as headache, myalgia, chills and fever, the study found. Of the 827 participants who completed their pregnancy, rates of miscarriage were the same as rates observed before the pandemic.
The findings are preliminary and covered just the first 11 weeks of the U.S. vaccine rollout, from Dec. 14 to Feb. 28.
Pregnant women are more likely to be hospitalized and run a higher risk of death when infected with Covid-19, making vaccination especially important to this demographic, according to CDC data. Pharmaceutical companies did not include pregnant women in early efficacy and safety studies, but evidence is mounting from recent studies that the vaccines are safe for them.
Researchers said "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."