One of the biggest reports of Covid-19 vaccination in pregnancy confirms it’s safe, although the authors say more extensive research is needed.
Preliminary results are based on reports from over 35,000 US women who received either Moderna or Pfizer images while pregnant. Their rates of miscarriages, premature births, and other complications were comparable to those seen in published reports of pregnant women before the pandemic.
The new findings from researchers at the Federal Centers for Disease Control and Prevention were published in the New England Journal of Medicine on Wednesday.
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None of the women involved received the Johnson & Johnson one-shot vaccine available after the study and is currently pending as US authorities investigate reports of blood clots in a handful of women.
Separately, the American Society for Reproductive Medicine on Tuesday approved vaccination in pregnancy based on evidence it has been evaluating for over a year.
Everyone, including pregnant women and those trying to get pregnant, should be given a Covid-19 vaccine. The vaccines are safe and effective, “the company said in a statement.
A company representative said the group had not evaluated the latest Johnson & Johnson vaccine findings.
A representative from the American College of Obstetricians and Gynecologists said the CDC report looked promising, but longer term follow-up was needed. This group previously said that Covid-19 vaccination should be available to pregnant women and women who are breastfeeding, and many pregnant US women have chosen to get vaccinated.
Although pregnant women were excluded from studies that resulted in emergency approval for the vaccines, the evidence showed no harm in women who were unknowingly pregnant at the time of enrollment.
Dr. Laura Riley, Obgyn chairman at New York’s Weill Cornell Medicine, said the new results are comforting.
“It’s great to have data for our patients that continues to weigh the risks and benefits of vaccination,” she said. “You know the possible complications of a Covid infection in pregnancy and now there is some safety data for pregnancies in humans.”
Pregnant women who become infected with the coronavirus are at increased risk of complications, including hospital stays in intensive care units, premature births, and death.
The authors of the study, led by Dr. Tom Shimabukuro, of the CDC, said continued surveillance and further evidence is needed, including for women who receive Covid-19 vaccinations in the early stages of pregnancy.
Their study included information on 35,691 pregnant US women who participated in a voluntary smartphone-based vaccination monitoring system and received Moderna or Pfizer vaccines between mid-December 2020 and late February.
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It also included reports of pregnancy complications from nearly 4,000 women enrolled on a U.S. vaccine safety registry. Of these, 86 percent, or 712, resulted in a live birth, mostly in women who were vaccinated in the third trimester.
Most of the women in the surveillance group reported injection site pain, but more serious reactions were less common. Pregnant women appeared to be more prone to injection site pain with both vaccines, but were less likely to experience different reactions than non-pregnant women.
In the vaccine register, about 13 percent of pregnant women reported miscarriages, less than 1 percent stillbirths, 9 percent premature births and 2 percent birth defects. These rates are all within the same range seen in reports in pre-pandemic pregnant women.