Rochester, Minnesota - Pregnant women are at an increased risk for serious illness if they become infected with COVID-19. Pregnant women have altered immune systems, and that could make them more susceptible to COVID-19. Also, research shows that pregnant women with underlying comorbidities or medical health conditions are at higher risk of having worse outcomes if they are infected. Compared to women who are not pregnant, have the same health conditions and are at the same age, a pregnant woman is about 1.3 to 1.4 times more likely to be hospitalized if infected with COVID-19.

While there are limited data about current COVID-19 vaccines in pregnant women and breastfeeding mothers, it is important to understand the risks and benefits for you and your baby. Early research indicates that antibodies induced by the vaccine, which are passed to the baby through the placenta and in breast milk, may be beneficial to the baby. Studies are ongoing and women should talk with their health care providers about any concerns.

But since the Food and Drug Administration granted emergency use authorization for COVID-19 vaccines, The American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine have firmly recommended that pregnant women have access to them if they so choose.

I have received many questions about whether a fetus can be exposed to COVID-19 by a mother being vaccinated for COVID-19. The answer is no. Any vaccine that has a live virus that replicates is not used in pregnant women because of any theoretical risk. The COVID-19 vaccines are not using live virus. Therefore, the baby should not be exposed to the virus, as the COVID-19 vaccines are the genetic code for a single protein. It doesn't replicate in a person. It doesn't cause an infection of COVID-19.

Because the COVID-19 vaccines are for emergency use, they were not tested in pregnant women during the first trials. So, there is no direct evidence of safety in pregnancy. What is known is that there is a lack of theoretical evidence of harm.

There is no reason why COVID-19 vaccines should harm pregnant women. None of the components of the vaccines — the nanoparticles — are known to be harmful in pregnancy. The best evidence for pregnant women suggests that being vaccinated for COVID-19 is a lot safer than getting COVID-19. Likewise, there is no indication that COVID-19 vaccines are harmful or damaging to women who are breastfeeding or to their infants.

Recently, a safety study compared women who were pregnant and not pregnant, and who received COVID-19 vaccines. The report showed no significant differences in reactions between the two groups.

The data review, which was performed by the Advisory Committee for Immunization Practices, indicates that over 30,000 women who are pregnant have safely been vaccinated for COVID-19. The preliminary safety study, which took place between December 2020 and January 2021, compared women who were pregnant and not pregnant, and who received the Pfizer or Moderna COVID-19 vaccines.

The advisory committee found that one day after vaccination, local reactions in both study groups were similar. In nearly all cases, no significant differences in reactions were experienced, such as localized pain, redness, fatigue, headache or fever.

Women who are pregnant and have received the COVID-19 vaccination are encouraged to participate in V-safe — a Centers for Disease Control and Prevention safety monitoring program following COVID-19 vaccination. These women are being followed at these specific intervals to monitor for longer-term adverse effects: once per trimester, after delivery and when the infant is 3 months old.

So far, 1,949 patients have been enrolled in the V-Safe monitoring program and 275 patients have completed pregnancies to date, including 232 live births. Pregnancy outcomes such as miscarriage, stillbirth, pregnancy complications and infant outcomes among participants are no different than general rates in women who are pregnant and have not been vaccinated for COVID-19.

I often am asked whether the vaccines could cause infertility and if women should wait to become pregnant if they are not already. There's no evidence of COVID-19 vaccines causing infertility. For my patients, I share the recommendation that women who are trying to conceive should stay on their contraception, go through the COVID-19 vaccination series and then revisit conception.

Although it is a personal choice for each person, COVID-19 vaccines are known to be effective. Knowing how dangerous infection can be in pregnancy, I believe that the benefits of the COVID-19 vaccine outweigh the risks for pregnant women.

Regardless of your decision, it is important that you — and everyone — continue social distancing and masking. — Dr. Regan Theiler, Obstetrics and Gynecology, Mayo Clinic, Rochester, Minnesota