For pregnant and nursing women, risks of COVID-19 probably outweigh risk of vaccine, experts say

Karen Weintraub, USA TODAY

Although there's very little data on how pregnant and nursing mothers will respond to a COVID-19 vaccine, professional organizations and individual doctors say the benefits are very likely to outweigh the risks.

Pregnant women appear to have the same chance of catching COVID-19 as everyone else. But they may fare worse if they do.

According to a November study by the U.S. Centers for Disease Control and Prevention, pregnant women are significantly more likely to be admitted to an intensive care unit, to end up on a ventilator, and to die from COVID-19 than women of the same age and health status who aren't pregnant.

So far, none of the large clinical trials of vaccines have included pregnant or nursing mothers, which is "incredibly disappointing," said Dr. Geeta Krishna Swamy, an obstetrician/gynecologist at Duke Medical Center, who helped write the vaccine guidelines for the American College of Obstetricians and Gynecologists (ACOG).

Pfizer and BioNTech, which make the first vaccine authorized for use in the U.S., says they are completing tests on animals to ensure its safety before beginning trials in pregnant women early next year. Moderna, whose vaccine was authorized this week, completed toxicology studies in rats, and a Food and Drug Administration review concluded it did not harm reproduction or fetal development.

Swamy, who was vaccinated Monday, said data from both vaccines reassured her that unless a woman is able to isolate at home during her pregnancy, the known risks of catching COVID-19 probably outweigh the theoretical risk of vaccination. The vaccine has been shown to be safe, she said, and "is likely one of the most effective vaccines we've ever had."

The risk, Swamy said, "can never be zero without data" but so far there's nothing to suggest that pregnant women and their unborn children won't be safe.

Most people won't have access to the vaccine for months, as vaccine is produced, there will probably be more data by the time most pregnant women have access to a shot.

But a large percentage of front-line health care workers are women of childbearing age and so are confronting this decision right now, as the first group of people receiving the vaccine.

"I personally feel comfortable recommending to those women that your risk-benefit balance suggests you should get vaccinated," Swamy said. "If a woman says I don't want to get vaccinated, I think that's absolutely, positively her choice, just like it's her choice to get vaccinated."

Swamy said she has even less concern about nursing mothers getting vaccinated. For the vaccine to harm a breastfed baby, she said, it would have to go from an arm into breast tissue and then into breast milk and then be digested by the baby. "That's a big task we're asking that vaccine to be able to do," she said. "The vaccine doesn't work if you swallow it."

The Academy of Breastfeeding Medicine shares her comfort with the COVID-19 vaccine for breastfeeding women, writing in their new guidelines that a vaccine "would be unlikely to have any biological effects" on a breastfed infant.

A woman who is vaccinated during pregnancy is likely to pass at least some protection on to her unborn child, with protection probably lasting some months after birth, Swamy said. Supplementing with breastmilk probably provides even longer-lasting antibodies.

Both vaccines showed similar safety and more than 94% effectiveness in large clinical trials that intentionally excluded pregnant women, although 23 women in the Pfizer-BioNTech trial and 13 in Moderna's became pregnant during the trial. Those groups were too small to judge safety or effectiveness, and anyone found to be pregnant after the first shot did not receive the second.

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The guidelines from the obstetricians and gynecologists group conclude that in the absence of specific data, a pregnant woman should make an individual decision about whether to get vaccinated. "ACOG recommends that COVID-19 vaccines should not be withheld from pregnant individuals," the guidelines say. Lactating women also should be given access to the vaccine, according to the group.

Pregnant women, the guidelines suggest, should base their decision in part on how much virus is circulating in their community, as well as the risks from a COVID-19 infection. A conversation with a clinician may be helpful, according to the guidelines, "but it should not be required prior to vaccination, as this may cause unnecessary barriers to access."

A study out of the University of California, San Francisco, that followed pregnant women after they tested positive for COVID-19, found that a quarter continued to suffer symptoms of the disease for eight or more weeks.

COVID-19 infection may also bring an increased risk of premature birth, said Dr. Denise Jamieson, chief of gynecology and obstetrics for Emory Healthcare in Atlanta.

There are perhaps 10 to 15 cases reported in the scientific literature where a baby born to a woman with COVID-19 tested positive for the disease at birth, she said in an hour-long webcast Wednesday provided by the American College of Medical Toxicology.

COVID-19 is unlikely to pass through breastmilk, Jamieson said. "I think in terms of our messaging about is it safe to breastfeed. ... There are benefits of breastfeeding that probably outweigh any small risks of transmission."

The government's V-safe monitoring system, set up to keep track of results from the vaccine, will specifically track pregnant women, Jamieson added, "so we should know more soon."

Contact Karen Weintraub at kweintraub@usatoday.com

Health and patient safety coverage at USA TODAY is made possible in part by a grant from the Masimo Foundation for Ethics, Innovation and Competition in Healthcare. The Masimo Foundation does not provide editorial input.

This article originally appeared on USA TODAY: COVID-19 vaccine, pregnancy: Benefits likely outweigh risks for women