Preliminary Findings of mRNA Covid-19 Vaccine Safety in Pregnant Persons

This U.S. surveillance review of the safety of mRNA Covid-19 vaccines during pregnancy and the periconception period indicates that some pregnant persons in the United States are choosing to be vaccinated against Covid-19 in all trimesters of pregnancy.

Solicited local and systemic reactions that were reported to the v-safe surveillance system were similar among persons who identified as pregnant and nonpregnant women. Although not directly comparable, the proportions of adverse pregnancy and neonatal outcomes (e.g., fetal loss, preterm birth, small size for gestational age, congenital anomalies, and neonatal death) among participants with completed pregnancies from the v-safe pregnancy registry appear to be similar to the published incidences in pregnant populations studied before the Covid-19 pandemic.

Abstract

BACKGROUND

Many pregnant persons in the United States are receiving messenger RNA (mRNA) coronavirus disease 2019 (Covid-19) vaccines, but data are limited on their safety in pregnancy.

METHODS

From December 14, 2020, to February 28, 2021, we used data from the “v-safe after vaccination health checker” surveillance system, the v-safe pregnancy registry, and the Vaccine Adverse Event Reporting System (VAERS) to characterize the initial safety of mRNA Covid-19 vaccines in pregnant persons.

RESULTS

A total of 35,691 v-safe participants 16 to 54 years of age identified as pregnant. Injection-site pain was reported more frequently among pregnant persons than among nonpregnant women, whereas headache, myalgia, chills, and fever were reported less frequently. Among 3958 participants enrolled in the v-safe pregnancy registry, 827 had a completed pregnancy, of which 115 (13.9%) resulted in a pregnancy loss and 712 (86.1%) resulted in a live birth (mostly among participants with vaccination in the third trimester). Adverse neonatal outcomes included preterm birth (in 9.4%) and small size for gestational age (in 3.2%); no neonatal deaths were reported. Although not directly comparable, calculated proportions of adverse pregnancy and neonatal outcomes in persons vaccinated against Covid-19 who had a completed pregnancy were similar to incidences reported in studies involving pregnant women that were conducted before the Covid-19 pandemic. Among 221 pregnancy-related adverse events reported to the VAERS, the most frequently reported event was spontaneous abortion (46 cases).

CONCLUSIONS

Preliminary findings did not show obvious safety signals among pregnant persons who received mRNA Covid-19 vaccines. However, more longitudinal follow-up, including follow-up of large numbers of women vaccinated earlier in pregnancy, is necessary to inform maternal, pregnancy, and infant outcomes.


Full paper

nejmoa2104983 (1)

Vaccinating Pregnant and Lactating Patients Against COVID-19 – From ACOG

Summary of Key Information and Recommendations – Full Text Link

  • ACOG recommends that pregnant individuals have access to COVID-19 vaccines.
  • COVID-19 vaccines should be offered to lactating individuals similar to non-lactating individuals.
  • Individuals considering a COVID-19 vaccine should have access to available information about the safety and efficacy of the vaccine, including information about data that are not available. A conversation between the patient and their clinical team may assist with decisions regarding the use of vaccines approved under EUA for the prevention of COVID-19 by pregnant patients. Important considerations include:
    • the potential efficacy of the vaccine
    • the risk and potential severity of maternal disease, including the effects of disease on the fetus and newborn
    • the safety of the vaccine for the pregnant patient and the fetus.
  • While a conversation with a clinician may be helpful, it should not be required prior to vaccination, as this may cause unnecessary barriers to access.
  • Similar to their non-pregnant peers, vaccination of pregnant individuals with a COVID-19 vaccine may occur in any setting authorized to administer these vaccines. This includes any clinical setting and non-clinical community-based vaccination sites such as schools, community centers, and other mass vaccination locations.
  • Pregnancy testing should not be a requirement prior to receiving any EUA-approved COVID-19 vaccine.
  • Unfounded claims linking COVID-19 vaccines to infertility have been scientifically disproven. ACOG recommends vaccination for all eligible people who may consider future pregnancy.
  • Pregnant patients who decline vaccination should be supported in their decision. Regardless of their decision to receive or not receive the vaccine, these conversations provide an opportunity to remind patients about the importance of other prevention measures such as hand washing, physical distancing, and wearing a mask.
  • Expected side effects should be explained as part of counseling patients, including that they are a normal part of the body’s reaction to the vaccine and developing antibodies to protect against COVID-19 illness.
  • Women under age 50 including pregnant individuals can receive any FDA-authorized COVID-19 vaccine available to them. However, they should be aware of the rare risk of TTS (thrombosis with thrombocytopenia syndrome) after receipt of the Janssen COVID-19 vaccine and that other FDA-authorized COVID-19 vaccines are available (i.e., mRNA vaccines).