TUESDAY, April 5, 2022 (HealthDay News) -- Public health experts have been telling pregnant women that it is safe -- and recommended -- to get a COVID-19 shot because they are at higher risk for poor outcomes and death from the virus.
New research now answers a key question about the vaccine's impact on their babies.
The vaccine is not associated with birth defects detectable on an ultrasound, the Northwestern University study found. Those major birth defects include the baby's heart not forming correctly or the spine not closing properly.
"One of the reasons women struggle with the vaccine in pregnancy is they're worried about their babies and don’t want to take any risks," said first author Dr. Rachel Ruderman, a fourth-year resident in obstetrics and gynecology at Northwestern's Feinberg School of Medicine in Chicago.
"This study shows there really is no increased risk of birth defects, and it supports other evidence that shows the vaccine is safe and beneficial for mom and baby," Ruderman said in a school news release.
About 3% to 5% of U.S. babies are affected by major birth defects.
In this study, the researchers used ultrasounds to look for major fetal structural abnormalities.
"During the early part of pregnancy when the organs are forming, there can be abnormalities in how they form, and they can take the form of birth defects that can have implications for the life of the child," said co-author Dr. Emily Miller, chief of obstetrics at Northwestern Medicine.
"For example, if the baby's heart isn't forming correctly, that could lead to the baby needing major cardiac surgery or long-term medication," Miller said in the release. "However, if the ultrasound identified extra fluid in the fetus' kidney, that might end up fixing itself down the road. We looked for those extremes and everything in between."
Pregnant women were excluded from clinical trials of COVID vaccines, which left a gap in information.
"This is yet another important piece of data that helps bridge the chasm that was left when pregnant individuals were excluded from those initial vaccine trials," Miller said.
The U.S. Centers for Disease Control and Prevention released similar findings in September.
The CDC's study used historical data as a comparison, but Northwestern used data from pregnant patients who either were not vaccinated at all or not within a window of 30 days prior to conception to 14 weeks' gestational age.
"I think the big strength of this study is that we compared against other women who were vaccinated, but at different point in their pregnancies," Miller said. "People who choose vaccination are often different from people who choose not to be vaccinated. Our study design helps account for some of those differences."
Researchers hope the findings will boost trust in the vaccines.
"Patients say, 'I don’t think the data is good, and everyone is getting COVID anyway, so why would I expose my baby?'" said Ruderman, who got her booster shot during her 12th week of pregnancy. "Then I tell people, 'Actually, the data is really good,' and I feel like they're receptive. So, these findings will only add to that."
The findings were published April 4 in JAMA Pediatrics. A similar study, out of Israel, was published in the same journal in February.
The U.S. Centers for Disease Control and Prevention has more on COVID-19 and pregnancy.
SOURCE: Northwestern University, news release, April 4, 2022