Women vaccinated against Covid-19 during pregnancy are at no increased risk of preterm or low birth weight, according to a study released Tuesday by the U.S. Centers for Disease Control and Prevention.
This is the latest in a series of studies that have shown Covid-19 vaccines to be safe for pregnant women.
Results are consistent for those who received Pfizer / BioNTech or Moderna vaccines and for those who were vaccinated in the second or third trimester. There was not enough data to analyze the risk in people vaccinated in the first trimester or with the Johnson & Johnson vaccine.
The CDC study included around 46,000 pregnant women, including around 10,000 who received at least one dose of Covid-19 during the vaccination. A premature birth was defined as less than 37 weeks gestation and low birth weight births are those where the baby’s birth weight was less than the tenth percentile for gestational age.
Pregnant women who present with a symptomatic case of Covid-19 face a double risk of admission and ventilation in the intensive care unit and an even higher risk of death compared to non-pregnant women who experience symptomatic infection, according to the researchers.
The CDC recommends vaccination for all pregnant women, recently pregnant, those who are trying to become pregnant, or who may become pregnant in the future. Still, the vaccination rate among pregnant women is low – only about a third of pregnant women have been vaccinated, according to the latest CDC data.
“Evidence of the benefits of vaccination against Covid-19 during pregnancy continues to accumulate, including the detection of antibodies in cord blood,” the researchers wrote. This suggests that immunizing pregnant women may also protect their newborns.
“Together, these findings reinforce the importance of communicating the risks of Covid-19 during pregnancy, the benefits of vaccination, and information on the safety and effectiveness of COVID-19 vaccination during pregnancy,” said they added.
The study does not take into account any potentially confounding factors, including a pregnant woman’s history of preterm or low birth weight or a previous infection with Covid-19. Additionally, the study group does not include those who may have been eligible for additional vaccine doses or booster shots during pregnancy.