Early studies show vaccinated mothers pass antibodies to babies

Researchers find it happens in utero, breast milk
pregnant women and covid-19 vaccine
Posted at 3:57 PM, Mar 23, 2021
and last updated 2021-03-23 19:28:16-04

KANSAS CITY, Mo. — Early studies show vaccinated pregnant women pass COVID-19 antibodies to their babies in utero as well as through breast milk.

"We have our first baby on the way, any day. We don't know boy or girl, but it's coming," said Sarah Bettis, a soon-to-be mom.

Bettis, who is expecting her first baby during a global pandemic, is a nurse practitioner at the University of Kansas Health System.

"I've been on the front lines not as much as my other colleagues, but we have definitely seen our fair share of COVID and navigating that while being pregnant was stressful," Bettis said.

Then, she was offered the option to get the vaccine.

"They recommended I get the vaccine and I felt good about that decision," Bettis said.

Studies show some vaccinated mothers pass COVID-19 antibodies to their newborns in utero.

"Once those antibodies have been produced in the maternal system, then they can readily cross through the placenta into the umbilical cord and into the baby," said Dr. Marc Parrish, OBGYN at the University of Kansas Health System.

Studies also show women who are still breastfeeding and are vaccinated can pass antibodies to their babies as well.

"Let's say that you have a mom that received the vaccination after pregnancy, but she is still actively breastfeeding her child. We know that there are antibodies in the maternal milk that will also cross into the baby's system," Parrish said. "These antibodies are a little bit different than the ones that are crossing through the placenta."

Parrish said antibodies could be present in a newborn's system anywhere from six to twelve weeks after they're born — a critical time as their immune systems develop.

"By having these maternal antibodies in their system, they are able to have that automatic protection that they are born with and keeps them safe until they are able to get their first vaccine," Parrish said.

Bettis said this news provides a sense of relief.

"Protecting myself during this pregnancy but also knowing that this baby might be born with some antibodies is adding stress relief and makes me feel so much better," Bettis said.

The University of Kansas Health System is not testing babies as these studies are in the pre-publication phase, which means they haven't yet been peer-reviewed.

"I don't have any doubt that if we were to test the children of mothers that have been vaccinated during pregnancy that those babies would have the antibodies in their system," Parrish said.