Preliminary Findings about COVID-19 Vaccine Safety during Pregnancy - A Message from NCBDDD

As a valued partner in the COVID-19 response, we want to ensure you are aware of an article published today in the New England Journal of Medicine: Preliminary Findings of mRNA COVID-19 Vaccine Safety in Pregnant Persons. This report describes the first U.S. data on the safety of mRNA COVID-19 vaccines administered during pregnancy, based on analyses of data from three vaccine-safety-related databases. The analyses did not identify any safety concerns for pregnant people who were vaccinated or for their infants. Many of the pregnancies are ongoing, so we have limited information on the outcomes among people vaccinated during their first or second trimester of pregnancy; additional follow-up is needed. However, these preliminary findings are reassuring. CDC will continue to collect information from people vaccinated during all trimesters of pregnancy and on the health of babies up to three months old to understand the benefits and risks of COVID-19 vaccination during pregnancy. We will update healthcare providers and the public about any new findings and provide additional information as it becomes available.

Key Findings (Data as of February 28, 2021)

  • More than 35,000 people in the v-safe active surveillance system reported receiving COVID-19 vaccine just before or during pregnancy. Generally, pregnant people reported similar side effects (type and frequency) compared with non-pregnant people after vaccination with mRNA COVID-19 vaccines.
  • More than 3,900 people who are/were pregnant have enrolled in the v-safe pregnancy registry, with 827 who have completed their pregnancies. The outcomes of pregnancies reported by people in the registry were similar to what we would expect among pregnant people who did not receive a vaccine in the general population (e.g., consistent with background rates for these outcomes).
    • About 14% (115) of pregnancies resulted in a pregnancy loss (104 miscarriages, 1 stillbirth).
    • About 86% (712) of pregnancies resulted in a live birth, most of which (~99%) were among people who received their first dose during the third trimester.
      • Health effects in newborns included preterm birth (9.4%, n=60), small for gestational age (3.2%, n=23), and major birth defects (2.2%, n=16).
  • These data are preliminary, but reassuring; no safety signals were detected. Many of the pregnancies in the registry are ongoing, and CDC will continue to follow up with these people. The majority of reports from completed pregnancies are from people vaccinated during their third trimester.
  • These preliminary findings contribute to what is known about the safety of COVID-19 vaccination during pregnancy and can help inform COVID-19 vaccination recommendations for people who are pregnant.

Call to Action

Pregnant people are more likely to get severely ill with COVID-19 compared with non-pregnant people. CDC recommends that if you are pregnant, you can receive a COVID-19 vaccine. Getting a COVID-19 vaccine during pregnancy can protect you from severe COVID-19. If you are facing a decision about whether to receive a COVID-19 vaccine while pregnant, consider your risk of exposure to COVID-19, the risks of severe disease, the known benefits of vaccination, and the limited but growing evidence on the safety of COVID-19 vaccines during pregnancy. A conversation with a healthcare provider may help you decide when to be vaccinated. 

A NEJM podcast featuring CDC Director, Dr. Rochelle Walensky, discussing these findings is also available. Thank you for your continued partnership and collaboration with the COVID-19 response.

Many thanks,

Suzanne Gilboa, PhD

Acting Director

Division of Birth Defects and Infant Disorders

National Center on Birth Defects and Developmental Disabilities

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