Should pregnant women get the COVID-19 vaccine? With little data, some are eager, some wary

Dr. Lauren Westafer, with her daughter Addie, wife Kate, and son Sloan, is a pregnant ER doctor, who was asked to help create a decision tool for pregnant women weighing whether to get the COVID vaccine.Jonathan Wiggs/Globe Staff

When COVID-19 vaccines became available late last year, Dr. Lauren Westafer faced a double challenge.

She’d been asked to help develop a guide for pregnant women and their doctors in deciding about vaccination. And Westafer, an emergency medicine physician at Baystate Health in Springfield, had just learned that she herself was pregnant.

She would have to navigate the very process she was developing for doctors and patients everywhere — and on that road she would confront a surprise: her emotions were suddenly running counter to the choice she had expected to make.

COVID-19 has brought a world of uncertainty, and none is greater than the question facing pregnant women about vaccination.

Pregnant women were excluded from the clinical trials of the COVID-19 vaccines. As a result, no one knows for sure whether the vaccines can endanger a pregnancy.

But this fact is known: Pregnant women are at significantly higher risk of severe illness from the virus.

“There’s no reason to believe the vaccine is unsafe. There’s a theoretical risk, versus the known proven risk of COVID in pregnancy,” said Dr. Linda Eckert, professor of obstetrics and gynecology at the University of Washington.

Among the more than 30,000 pregnant women who had taken the vaccine by Feb. 16, the Centers for Disease Control and Prevention found no safety problems, no evidence that miscarriages, stillbirths, preterm births, or other problems were more common among vaccinated women than among the unvaccinated. In animal studies, all three vaccines were found safe for pregnant mammals. Studies in people are under way.

There is no known biological mechanism by which the vaccines could harm the fetus, said Dr. Khady Diouf, an obstetrician-gynecologist and infectious disease specialist at Brigham and Women’s Hospital. Still, Diouf added, “You can’t say 100 percent that there aren’t untoward side effects we didn’t think about.”

But the vaccine confers benefits beyond protecting the mother. The antibodies it produces are transferred to the baby during pregnancy and breastfeeding, potentially protecting the baby. And Eckert notes that vaccines can reduce isolation — vaccinated women may feel more comfortable accepting support from others after childbirth.

In Massachusetts, pregnant health care workers or teachers, or expectant mothers who have an additional health condition, have been eligible for the vaccine for weeks. The state is not tracking how many pregnant people have been vaccinated.

A much broader group will confront the question starting April 5 when state rules will allow people with only one health condition, including pregnancy, to sign up for the vaccine.

As a physician and front-line caregiver, Westafer, the Baystate doctor, was eligible in December. She had studied the vaccine trial results and thought they looked good, even though pregnant women were not included. While trying to get pregnant, she fully expected she’d take the vaccine.

That changed the day she got her pregnancy test results. “I did a 180 in that moment,” she said. Suddenly, the vaccine looked too risky.

Even in the best of circumstances, Westafer explained, some 15 percent to 20 percent of pregnancies end in miscarriage, and 4 percent of babies are born with a congenital abnormality. If something went wrong with her pregnancy after she got vaccinated, would she blame herself, even though it might have happened without the vaccine?

In two previous pregnancies, she’d taken the flu and Tdap (tetanus, diphtheria, pertussis) vaccines without batting an eye. But with these new COVID-19 vaccines, she had to ask, “Is there something to worry about here?”

No one knows of any way the vaccine could cross the placenta or harm a pregnancy. But it hadn’t been studied. “‘We don’t know’ is the major concern,” she said.

But then Westafer had to come back to what is known. Pregnant people are five times more likely to end up in intensive care if they get COVID-19, and also more likely to have a preterm birth or die.

Westafer is 36, considered an advanced maternal age, which heightens other risks. What if she got COVID-19 and went into preterm labor? Women tend to focus on the health of the fetus and baby, she said, but their own health is equally important. “If you don’t live, the baby also doesn’t live,” she said.

As an emergency physician at Baystate Health, which in the winter routinely had more than 150 COVID-19 patients, Westafer was exposed to COVID-19 daily. And she had seen pregnant women get seriously ill with it.

On Dec. 18, six weeks pregnant, Westafer received her first dose of the Pfizer vaccine.

Shortly afterward, Westafer and colleagues released their guide to deciding about COVID vaccination during pregnancy, which has since been translated into 10 languages and is being used in hospitals around Massachusetts and elsewhere.

The document was updated on Wednesday. Both the earlier and current versions lean in favor of vaccination, stating: “For most people, getting the COVID vaccine as soon as possible is the safest choice.”

That’s arguably a stronger stance than those taken by national medical groups.

The American College of Obstetricians and Gynecologists advises that providers should not withhold the COVID-19 vaccine from pregnant women who want it, but stops short of urging women to take it. Likewise, the CDC calls the decision “a personal choice.”

Those are not the full-throated endorsements that a pregnant woman might like to have.

But Eckert, a coauthor of the ACOG statement, said doctors couldn’t go beyond the facts at hand. “We reviewed the data, and listened to the evidence. Because there’s no phase three pregnancy trials using these vaccines, we couldn’t recommend it at this time,” she said.

Dr. Margaret Sullivan, an obstetrician-gynecologist at Tufts Medical Center, said she would never push her patients toward a decision, but rather guides their thinking with information.

“I don’t encourage. I would never recommend that they get it,” she said. Instead she asks about about their risk of exposure to COVID-19 and discusses the knowns and unknowns about the vaccine. “People are nervous,” Sullivan said. “They don’t want to put their baby at risk.”

Westafer, the pregnant doctor at BayState Health, said pregnant women anxious about the vaccine could reasonably decide to forgo or delay it, particularly if they are able to avoid exposure to the virus.

“I’m not sure I would have gotten the COVID vaccine that early in my pregnancy if I worked at home, if my kids didn’t go to day care, if I was able to isolate myself,” she said.

Also, people interpret data and assess risk in different ways, she said: “Often it’s driven by emotion, and that’s not necessarily wrong, especially when it comes to something like pregnancy.”

“In pregnancy,” Westafer said, “we don’t get certainty — really ever.”