Association of COVID-19 Vaccination in Pregnancy With Adverse Peripartum Outcomes

Abstract

IMPORTANCEThere is limited comparative epidemiological evidence on outcomes associated with COVID-19 vaccination during pregnancy; monitoring pregnancy outcomes in large populations is required.OBJECTIVE To evaluate peripartum outcomes following COVID-19 vaccination during pregnancy. DESIGN, SETTING, AND PARTICIPANTSPopulation-based retrospective cohort study in Ontario, Canada, using a birth registry linked with the provincial COVID-19 immunization database. All births between December 14, 2020, and September 30, 2021, were included.EXPOSURES COVID-19 vaccination during pregnancy, COVID-19 vaccination after pregnancy, and no vaccination.MAIN OUTCOMES AND MEASURES Postpartum hemorrhage, chorioamnionitis, cesarean delivery (overall and emergency cesarean delivery), admission to neonatal intensive care unit (NICU), and low newborn 5-minute Apgar score (<7). Linear and robust Poisson regression was used to generate adjusted risk differences (aRDs) and risk ratios (aRRs), respectively, comparing cumulative incidence of outcomes in those who received COVID-19 vaccination during pregnancy with those vaccinated after pregnancy and those with no record of COVID-19 vaccination at any point. Inverse probability of treatment weights were used to adjust for confounding. RESULTS Among 97 590 individuals (mean [SD] age, 31.9 [4.9] years), 22 660 (23%) received at least 1 dose of COVID-19 vaccine during pregnancy (63.6% received dose 1 in the third trimester; 99.8% received an mRNA vaccine). Comparing those vaccinated during vs after pregnancy (n = 44 815), there were no significantly increased risks of postpartum hemorrhage (incidence: 3.0% vs 3.0%; aRD, −0.28 per 100 individuals [95% CI, −0.59 to 0.03]; aRR, 0.91 [95% CI, 0.82-1.02]), chorioamnionitis (0.5% vs 0.5%; aRD, −0.04 per 100 individuals [95% CI, −0.17 to 0.09]; aRR, 0.92 [95% CI, 0.70-1.21]), cesarean delivery (30.8% vs 32.2%; aRD, −2.73 per 100 individuals [95% CI, −3.59 to −1.88]; aRR, 0.92 [95% CI, 0.89-0.95]), NICU admission (11.0% vs 13.3%; aRD, −1.89 per 100 newborns [95% CI, −2.49 to −1.30]; aRR, 0.85 [95% CI, 0.80-0.90]), or low Apgar score (1.8% vs 2.0%; aRD, −0.31 per 100 newborns [95% CI, −0.56 to −0.06]; aRR, 0.84 [95% CI, 0.73-0.97]). Findings were qualitatively similar when compared with individuals who did not receive COVID-19 vaccination at any point (n = 30 115). CONCLUSIONS AND RELEVANCEIn this population-based cohort study in Ontario, Canada, COVID-19 vaccination during pregnancy, compared with vaccination after pregnancy and with no vaccination, was not significantly associated with increased risk of adverse peripartum outcomes. Study interpretation should consider that the vaccinations received during pregnancy were primarily mRNA vaccines administered in the second and third trimester.

Management and outcomes of pregnant women admitted to intensive care unit for severe pneumonia related to SARS-CoV-2 infection: the multicenter and international COVIDPREG study

“…Third, our results are not generalizable to newly emerging SARS-CoV-2 variants and to pregnant women who have received immunomodulatory treatments and/or who have been vaccinated. It has been suggested very recently that vaccination may be associated with lower maternal respiratory severity without adverse peripartum outcomes [ 33 – 35 ]. Finally, we did not study the management of analgesia during labor in patients who were not intubated for delivery and further studies are needed to specifically address this issue.…”

COVID-19 Vaccines Confer Protection in Hospitalized Pregnant and Postpartum Women with Severe COVID-19: A Retrospective Cohort Study

“…Most of the subjects received the Pfizer/BioNTech or Moderna vaccines, and available data do not demonstrate adverse outcomes or side effects of vaccination during pregnancy [ 20 , 22 , 37 , 38 , 39 , 40 , 41 ]. Shimakaburo et al evaluated the outcomes of 827 completed pregnancies.…”

Covid-19 vaccination in pregnancy

“…Nine studies evaluated NICU admission rates after maternal vaccination, and none identified an increased risk 363842505764707478. The largest study found that overall rates of adverse newborn outcomes were lower among those born to people vaccinated during pregnancy versus those vaccinated afterwards, including lower NICU admission (11.0% v 13.3%; adjusted risk ratio 0.85, 0.80 to 0.90) 78.…”