It’s a struggle for many expectant parents and there are limited studies to help in the decision-making process.
When it comes to COVID-19, the risks for pregnant women are well documented – hospitalizations and ICU admissions are higher.
Dr. Emily Miller is a maternal fetal medicine specialist with Northwestern Medicine.
“As the uterus grows bigger there is compression of the lung space and so there is not as much area for ventilation or exchange of air,” she said.
And the immune system plays a role.
Jeffery Goldstein is a Northwestern Medicine pathologist.
“Part of the issue is the mother’s body is working harder,” he said. “She is circulating more blood.”
“Most pregnant women do fine and they recover and their baby does fine,” Miller said.
When the Covid vaccines arrived there was both celebration and questions. Pregnant women were left out of clinical trials.
“As soon as the vaccines came out, we started getting emails,” Goldstein said.
“Pregnant people have been put in a really tough place, where there just hasn’t been data,” Miller said.
To help bridge the safety information gap, Northwestern Medicine doctors looked to the placenta for any possible signs of harm caused by the fast-tracked immunizations.
“From our perspective, we think about the placenta as the black box in an airliner,” Goldstein said.
It’s a remarkable tool. The placenta not only sustains life – it delivers oxygen and nutrients and keeps a developing baby safe from infection and the outside world — it even tracks problems that can arise during pregnancy.
“If the pregnancy is normal and everything is going fine, you really shouldn’t find any abnormalities there,” Goldstein said. “If something bad happens, then looking at the placenta is one of the most straightforward ways to figure out if something is going wrong.”
In the lab, they looked at placentas from 120 vaccinated and 200 unvaccinated women.
“The good news is in this cohort study comparing placentas of pregnant women who got vaccination during their pregnancy to controls who did not get a vaccination, there is absolutely no difference in the placenta,” Miller said. “No increased risks in any of the harms we looked for. And we took a pretty deep dive to make sure we weren’t missing anything.”
Their investigation revealed another finding. In women who received the COVID-19 vaccine, antibodies crossed the placental barrier, providing passive immunity to the fetus. The same happens when expectant moms receive influenzas and pertussis vaccines.
“The placenta has a specialized protein that captures antibodies from the maternal circulation and carries them over into the fetal circulation,” Goldstein said. “It’s a feature something the placenta is supposed to be doing.”
“I hope this can flip our narrative from wanting to avoid the risks of the vaccination to wanting to get the benefits of the vaccine,” Miller said.
Researchers will be studying pregnancy in the covid era for decades to come. Long-term data tracking babies in utero at the time of the 1918 Spanish flu show a higher risk for heart disease and lower incomes.