BJC and Saint Luke’s Officially Combine as BJC Health System

What pregnant people should know about vaccines, boosters and omicron

BJC Heroes WIP inside ashley

Ebony Carter, MD, wants pregnant people to know that when they’re vaccinated and boosted against COVID-19, the only thing they’ll be passing on to their unborn child is a better chance at a healthy start in life.

Dr. Carter, a Washington University high-risk gynecologist/obstetrician at Barnes-Jewish Hospital, has seen it in her own practice — patients who are concerned that the COVID-19 vaccine will cause harm to their babies.

But she’s quick to reassure them that extensive research shows that the vaccine and booster are the best way to help protect moms and babies from serious COVID-19 complications, including hospitalization, premature birth or stillbirth, and they are infinitely safer than getting infected with COVID while pregnant.

Studies also show that women who are vaccinated and boosted pass on high levels of protective antibodies to their babies. The protection appears to last through the newborn’s first few months of life.

Boosters are even better

Pregnancy causes changes to the body that make women more susceptible to infection and more likely to become severely ill if they become infected with COVID-19, according to the Centers for Disease Control and Prevention (CDC).

For instance, the body’s immune system shifts into low gear to keep it from identifying the developing baby as a foreign object and attacking it. This lowered ability to fight infection is one reason pregnant people are more likely to develop serious COVID-19 complications — and not being vaccinated makes the situation even more dangerous.

“Pregnant people have the potential to get a lot sicker than the non-pregnant version of themselves,” Dr. Carter says.

Data shows that unvaccinated pregnant people had three times the risk of being hospitalized or needing intensive care, and double the risk of needing total heart and lung support through ECMO. Serious complications in the mother also can cause problems for the baby, raising the risk of premature delivery or even stillbirth.

But it’s a starkly different picture for moms who get the vaccine, especially for those who get a booster.

A lower risk

While the vaccine may not prevent infection with COVID-19, pregnant people who have received two vaccine doses are 60% less likely to need hospitalization. Those who also have had the booster shot are 90% less likely to be hospitalized.

A highly contagious COVID-19 variant, such as omicron, puts more pregnant people at risk and makes vaccination even more important, says Dr. Carter. 

When the delta variant surged this past August, only 20% of pregnant people admitted to the hospital tested positive. At the height of the omicron surge in the St. Louis region, about 45% of pregnant people admitted to Barnes-Jewish Hospital tested positive for COVID-19, she says. “We’ve never seen numbers this high.”

Although there are signs that omicron symptoms might be slightly milder than previous COVID-19 strains, the recent omicron surge that filled emergency departments and ICUs to capacity shows that omicron definitely can produce severe symptoms.

But as with other COVID-19 strains, research shows that pregnant people who are vaccinated and boosted are at very low risk of hospitalization or death from omicron.

Protecting baby

The best vaccine news for pregnant people may be studies which show that babies of mothers who had been vaccinated during pregnancy were born with antibodies that protect against COVID-19.

One study found that babies whose mothers had been vaccinated had even higher levels of protective antibodies in their blood than babies whose mothers had recovered from a natural COVID-19 infection.

Researchers also found that antibodies are plentiful in the breast milk of vaccinated mothers and may provide babies with additional protection against COVID-19 infection.

Unfortunately, some pregnant people are distressingly hesitant to be vaccinated, says Dr. Carter. According to data from the CDC, as of Jan. 1, 2022, just over 40% of pregnant people in the U.S. between ages 18 and 49 were fully vaccinated prior to pregnancy or during their pregnancy.

“I wish they could just look over my shoulder when I’m taking care of patients who refuse the vaccine and they’re struggling to breathe or are on ventilators in the ICU,” Dr. Carter says.  

She urges people who are pregnant or thinking about getting pregnant to learn as much as they can about the vaccine and discuss the benefits and risks with their physician or midwife.

“I think it’s important that everybody is armed with the information they need to make the best decisions for themselves and their families,” she says.

Getting vaccinated just might be a lifesaving decision for birthing people and their babies.

We encourage you to discuss any questions or concerns you may have with your Ob/Gyn or maternity care provider. To find an Ob/Gyn, go to bjc.org/specialties/obstetrics-and-gynecology.

Sign up for our newsletter and take charge of your whole health.

Stay ahead of the curve with exclusive content from BJC's health care professionals, delivered right to your inbox.