A new study says pregnant people experience few side effects from the COVID-19 vaccine

• New research shows pregnant women report fewer vaccine-related side effects.
• The findings could be coincidental, but add to research showing the shots are safe in pregnancy.
• Leading medical organizations now recommend pregnant people get the COVID-19 vaccine.

When it comes to side effects from the COVID-19 vaccine, pregnant people may fare better than their non-pregnant peers, new research suggests.

The paper, published Tuesday in JAMA Network Open, adds to mounting evidence that the shots are safe, effective, and well-tolerated in pregnancy, and follows new guidance from the Centers for Disease Control and Prevention recommending the jabs in all pregnant women.

The research included more than 17,000 people

The report, out of the UW Medicine in Seattle, surveyed more than 17,000 vaccinated people - 7,770 of whom were pregnant, 6775 of whom were lactating people, and the rest who were used as a non-pregnant comparison group. The researchers wanted to see how the groups' shot-related symptoms differed, if at all.

Almost all participants, about 90% across all groups, experienced site injection pain after each dose. But other side effects were less common among the pregnant patients. For example, 45% of all participants reported a fever after the first dose, but that percentage shrunk to 30% when looking just at those who were pregnant.

Some pregnant people have been concerned about a vaccine-related fever during pregnancy, since a high, persistant one can be dangerous in the first trimester. However, the American College of Obstetricians and Gynecologists recommends taking Tylenol if a fever crops up. Plus, COVID-19 is more likely to lead to a fever than the vaccine.

Pregnant study participants were also less likely to experience fatigue, body aches, headaches, and chills after their shots. Lactating moms generally reported fewer side effects than the control group, but more than the pregnant group.

The results could be coincidental, but they're still encouraging

It's not clear if pregnancy provides some sort of protective effect against vaccine side effects. It's possible some pregnant people chalked up their malaise to pregnancy, not the vaccine, or didn't notice minor vaccine side effects while coping with more prominent pregnancy-related ones, like morning sickness.

The results could also be coincidence: Other studies have shown no significant differences in vaccine symptoms between pregnant and non-pregnant patients.

But the report does underscore that pregnant women don't seem to be at any increased risk of negative outcomes, though clinical trials are ongoing."Pregnant people do well with the vaccine," lead author Dr. Alisa Kachikis said in a news release.

Medical organizations are now recommending the vaccine in pregnancy

Early on, clinicians trusted that the shots are safe in pregnancy, but didn't have the rigorous clinical trial evidence to support it.

Since then, more evidence has come out in support of the vaccine during pregnancy, though clinical trial data remains pending. Data from three safety monitoring systems didn't find safety concerns for vaccinated pregnant people or their babies.

Most recently, the CDC revealed a new analysis finding no increased risk of miscarriage among nearly 2,500 pregnant women who received the Pfizer or Moderna vaccine before 20 weeks of pregnancy. About 13% of recipients experienced miscarriage, which is in line with the rate in the general population.

Given their safety, efficacy, the increased risk of severe illness from COVID-19 in pregnancy, and the rise in COVID-19 cases from the highly contagious Delta variant, "it has never been more urgent to increase vaccinations as we face," CDC Director Rochelle Walensky said in a statement last week.

Earlier this month, only about 23% of pregnant people had received the vaccine.