The COVID-19 vaccine wasn’t tested in pregnancy, but experts say it’s still worth considering if you’re expecting

As health-care workers prepare to receive Pfizer’s COVID-19 vaccine starting this week, a Centers for Disease Control and Prevention committee has recommended that pregnant workers — a group typically excluded from vaccine trials — still be allowed to decide with their doctors whether to receive the vaccine.

The majority of health-care workers are women, and Johns Hopkins University researchers noted in STAT News last week that an estimated 330,000 in this workforce “will be pregnant or breastfeeding as initial doses of vaccine are being distributed.” Even more could become pregnant in the weeks between administration of the two doses of vaccine required for full protection from the virus.

The New York Times reported this weekend that the CDC committee’s discussion on pregnancy and the vaccine focused on the large number of pregnant health-care workers at risk of getting the virus.

Pregnant women were not included in Pfizer’s vaccine trials earlier this year, but about two dozen people who got the vaccine became pregnant while participating in the studies. None reported complications.

Larger-scale vaccination distribution will inevitably include women who don’t yet know they’re pregnant, or who become pregnant while in between the two-shot vaccine regimen, so the CDC should monitor such women for adverse side effects, said Paul Offit, a member of the advisory panel that recommended emergency approval of the vaccine to the Food and Drug Administration last week.

Offit, a pediatrician who directs the Vaccine Education Center at Children’s Hospital of Philadelphia, said that although there were not sufficient data on the vaccine in pregnancy, there is no “real or even theoretical risk for pregnancy or the unborn child,” because of how the Pfizer vaccine is made. Still, for pregnant women unwilling to be inoculated, careful precautions can protect them while the virus continues to rage. “The best thing you can do is mask and social-distance,” he said.

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Some obstetricians say that they would advise that their pregnant patients should be allowed to receive the vaccine because they’re at a higher risk of serious complications from the virus.

According to CDC data, of the more than 44,000 pregnant women in the United States who have tested positive for COVID-19 over the course of the pandemic, more than 8,500 had to be hospitalized, at least 300 of them in intensive care, and 57 have died.

“It’s known that pregnant women can be a bit sicker if they get COVID-19,” said Vincenzo Berghella, a physician who specializes in high-risk pregnancy at Jefferson University Hospital. “If they get the severe disease — meaning they get pneumonia, and they need oxygen, they’re at a slightly higher risk of needing to be intubated, and to end up in the intensive care unit, and maybe even to die.”

People of color generally face a higher risk of serious COVID-19 complications, and the same is true during pregnancy. What’s more, even without the virus, women of color have faced higher rates of serious and even fatal complications during childbirth.

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Berghella said that although the vaccine shouldn’t be mandatory, he believes it’s important for pregnant women to take it.

“These types of vaccines, they don’t contain an alive virus — so they shouldn’t cause any issue to the fetus,” he said. “There’s really no theoretical risks we know of.”

The Pfizer vaccine, the first to be distributed, is made not with weakened or inactivated whole viruses, but with molecules called messenger RNA. These contain genetic instructions for human cells to make the “spike” protein that has become familiar in images of coronavirus particles. Clinical trial results indicate that the spike protein is enough to prompt a protective response — and a protein cannot cause infectious disease on its own.

Pregnancy typically excludes people from participating in vaccine studies, although expectant moms should get flu vaccines since they are at higher risk of serious problems related to flu. Berghella says excluding pregnant women from trials is a mistake, especially during the COVID-19 pandemic, because the first wave of Americans to receive the virus will be health-care workers, most of whom are women.

“People working in hospitals, from cleaning staff to midwives, who are pregnant shouldn’t be withheld from getting the vaccine,” said Berghella.

» READ MORE: Health care workers are top priority to get the COVID-19 vaccine, but not all want it, or must get it

In Philadelphia, a city ordinance requires most employers to accommodate the needs of pregnant employees, said Margaret Zhang, a staff attorney at the Women’s Law Project. During the pandemic, pregnant women in health care have used the law to continue to work but to stay out of contact with COVID-19 patients, she said. That law doesn’t apply elsewhere in the state, however.

The American College of Obstetricians and Gynecologists wrote in a statement last week that the organization is “closely monitoring new developments” and has urged the FDA to address the use of the vaccine on pregnant and lactating patients. “ACOG feels strongly that the vaccine should not be withheld from pregnant individuals,” they wrote.

In a list of recommendations released Monday, the organization said conversations with their doctors can help pregnant patients decide whether to take the vaccine, and that they should consider the spread of the virus in their communities, the efficacy of the vaccine (95% in clinical trials) the risk of getting sick during pregnancy and the safety of the vaccine before making a decision.

The organization said pregnant patients shouldn’t be required to speak with a doctor before vaccination, though, “as this may cause unnecessary barrier to access.” They added that pregnant patients who choose not to receive the vaccine “should be supported in their decision.”

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Pregnant and lactating people should be included in more clinical vaccine trials in the future, the group said, so others can make informed decisions about vaccinations while they’re pregnant.