Administration of mRNA COVID-19 vaccine during pregnancy not tied to increased risk of adverse pregnancy outcomes: Study

Recent study aimed to evaluate the association between receiving an mRNA COVID-19 vaccine during pregnancy and the risk of adverse pregnancy outcomes. This was a retrospective cohort study of 55,591 individuals with singleton pregnancies and live deliveries between June 2021 and January 2022, using data from eight integrated U.S. health care systems in the Vaccine Safety Datalink.

Vaccine Uptake and Demographics -

The study found that 42.3% of individuals received one or two doses of an mRNA COVID-19 vaccine during their pregnancy. Vaccine uptake varied by maternal characteristics, with older, non-Hispanic Asian individuals more likely to be vaccinated, and Hispanic and non-Hispanic Black individuals less likely to be vaccinated.

Association with Preterm Birth and Neonatal Outcomes -

After accounting for potential confounding factors through propensity score weighting, the study found that receiving an mRNA COVID-19 vaccine during pregnancy was associated with a lower risk of preterm birth (adjusted hazard ratio [aHR] 0.89, 95% CI 0.83-0.94) compared to no vaccination. There was no association between vaccination and risk of small-for-gestational-age neonates (aHR 1.06, 95% CI 0.99-1.13).

Maternal Outcomes Regarding Vaccination -

For maternal outcomes, the study found no association between receiving an mRNA COVID-19 vaccine and the risk of gestational diabetes (adjusted relative risk [aRR] 1.00, 95% CI 0.90-1.10), gestational hypertension (aRR 1.08, 95% CI 0.96-1.22), or preeclampsia-eclampsia-HELLP syndrome (aRR 1.10, 95% CI 0.97-1.24), when vaccination occurred before 20-22 weeks of gestation.

Conclusion and Clinical Implications -

The authors concluded that receiving an mRNA COVID-19 vaccine during pregnancy was not associated with an increased risk of adverse pregnancy outcomes. They noted that this information will be helpful for patients and clinicians when considering COVID-19 vaccination in pregnancy.

Strengths and Limitations of the Study

Key strengths of the study included the large, diverse cohort from multiple integrated health systems, the detailed data on vaccine exposure and pregnancy outcomes, and the use of robust statistical methods to address potential confounding. Limitations included potential residual confounding, inability to fully capture all COVID-19 infections, and challenges in precisely ascertaining the timing of onset for some pregnancy complications.

Reassuring Evidence from the Study

Overall, this study provides reassuring evidence that mRNA COVID-19 vaccination during pregnancy is not associated with an elevated risk of adverse pregnancy outcomes such as preterm birth, small-for-gestational-age, gestational diabetes, gestational hypertension, or preeclampsia. The findings can help inform decision-making around COVID-19 vaccination for pregnant individuals.

Key Points -

1. The study aimed to evaluate the association between receiving an mRNA COVID-19 vaccine during pregnancy and the risk of adverse pregnancy outcomes using data from eight integrated U.S. health care systems in the Vaccine Safety Datalink.

2. The study found that receiving an mRNA COVID-19 vaccine during pregnancy was associated with a lower risk of preterm birth compared to no vaccination, but there was no association between vaccination and the risk of small-for-gestational-age neonates. Additionally, the study found no association between receiving an mRNA COVID-19 vaccine and the risk of gestational diabetes, gestational hypertension, or preeclampsia-eclampsia-HELLP syndrome when vaccination occurred before 20-22 weeks of gestation.

3. The authors concluded that receiving an mRNA COVID-19 vaccine during pregnancy was not associated with an increased risk of adverse pregnancy outcomes, and this information can be helpful for patients and clinicians when considering COVID-19 vaccination in pregnancy.

Reference –

Vesco, Kimberly K. MD, MPH; Denoble, Anna E. MD, MSc; Lipkind, Heather S. MD, MS; Kharbanda, Elyse O. MD, MPH; DeSilva, Malini B. MD, MPH; Daley, Matthew F. MD; Getahun, Darios MD, PhD; Zerbo, Ousseny PhD; Naleway, Allison L. PhD; Jackson, Lisa MD, MPH; Williams, Joshua T.B. MD; Boyce, Thomas G. MD, MPH; Fuller, Candace C. PhD; Weintraub, Eric S. MPH; Vazquez-Benitez, Gabriela PhD, MS. Obstetric Complications and Birth Outcomes After Antenatal Coronavirus Disease 2019 (COVID-19) Vaccination. Obstetrics & Gynecology 143(6):p 794-802, June 2024. | DOI: 10.1097/AOG.0000000000005583