close up of a COVID-19 spike

What to know about pregnancy and COVID-19 vaccines

Much more is known about COVID-19 and pregnancy now that we’re a year into the pandemic.

Fortunately, in the majority of cases, SARS-CoV-2 infection during pregnancy turns out well. COVID-19 can be worsened, however, by the extra work of breathing and stress on the heart that occur with pregnancy.

Pregnant women with COVID-19 have twice the risk of admission to an intensive care unit, three times the risk of requiring mechanical ventilation and an increased probability of dying compared to uninfected pregnant women. Pregnant women with health problems such as obesity, lung and heart issues are at the greatest risk for having problems.

For the most part, babies fare well if their mother becomes infected during pregnancy. There doesn’t seem to be any increase in birth defects or miscarriages. There is, however, a small rise in preterm deliveries associated with moderate to severe COVID-19 during the later part of pregnancy. Most babies born to mothers infected test negative for the virus at birth. Even those that test positive do well.

In the past, pregnant women were denied vaccines out of fear for their unborn child. This is now felt to be unethical as each woman has the right to determine what is best for her and her child. When making such a decision, it is important to know a few things about vaccines.

Most vaccines are safe for the mother and child during pregnancy. We now know it’s important that women receive a tetanus-diphtheria-pertussis and flu vaccine during pregnancy to protect themselves and their babies. We’ve stayed away from giving weakened live virus vaccines such as the measles, mumps, rubella vaccine to pregnant women because of a theoretical risk of infecting the baby with a vaccine virus.

Over the decades, hundreds of thousands of pregnant women received these vaccines accidentally because they were unaware that they were pregnant. Their babies didn’t suffer any ill effects from the vaccinations.

The Pfizer and Moderna COVID-19 vaccines contain messenger RNA and are not live vaccines. Moderna has completed studies on pregnant animals and nothing of concern was found. Pfizer is performing similar animal studies. More information will become available as the small number of volunteers who became pregnant on the Pfizer and Moderna clinical trials deliver. Vaccine trials specifically for pregnant women are just beginning.

The U.S. Centers for Disease Control and Prevention, the American College of Obstetricians and Gynecologists and the Society of Maternal-Fetal Medicine all recommend pregnant women be offered the vaccine.

It’s a pregnant woman’s personal decision whether to be vaccinated. Each mother should consider her risk of contracting the virus along with her medical conditions. Vaccinated or not, pregnant women should continue social distancing, wearing masks and keeping up with their prenatal care.

Vaccine Smarts is written by Sealy Institute for Vaccine Sciences faculty members Drs. Megan Berman, an associate professor of internal medicine, and Richard Rupp, a professor of pediatrics at the University of Texas Medical Branch. For questions about vaccines, email