Postpartum hemorrhage emerges as a key outcome of maternal SARS-CoV-2 omicron variant infection surge across pregnancy trimesters

Abstract

Background: Despite evidence showing changes in disease severity with the virus's evolution and vaccination efforts, the link between maternal, perinatal, and neonatal outcomes and SARS-CoV-2 infections during different pregnancy trimesters remains unclear, especially with the BA.5 and BF.7 Omicron subvariant surge in China in December 2022. This study investigates the correlation between maternal, perinatal, and neonatal outcomes and SARS-CoV-2 infection across various pregnancy trimesters.

Methods: This prospective cohort study was conducted at two hospitals in southwest China, examining the clinical records and infection status of 2158 pregnant women registered between January 1, 2022, and September 30, 2023. Initially shielded from COVID-19, the population later experienced a significant infection surge. A comparative analysis evaluated maternal, perinatal, and neonatal outcomes between infected and uninfected subjects. Primary outcomes included pregnancy complications and premature births, while secondary outcomes encompassed cesarean sections, delivery complications, and neonatal outcomes.

Results: Pregnant women infected with SARS-CoV-2 had higher incidence of placenta increta/percreta and postpartum hemorrhage compared to uninfected women. First trimester infections were associated with a lower incidence of intrahepatic cholestasis of pregnancy [aOR = 0.29, 95 % CI 0.13-0.63] but a higher incidence of preterm birth [aOR = 2.16, 95 % CI 1.25-3.71]. Third trimester infections increased the risk of postpartum hemorrhage [aOR = 2.74, 95 % CI 1.21-6.18].

Conclusion: SARS-CoV-2 infection during pregnancy is linked to increased incidence of placenta increta/percreta and postpartum hemorrhage. First trimester infections are associated with higher incidence of premature birth and lower incidence of intrahepatic cholestasis of pregnancy, while third trimester infections are linked to higher incidence of postpartum hemorrhage.

Keywords: Maternal and neonatal outcomes; Postpartum hemorrhage; Preterm birth; Prospective cohort study; SARS-CoV-2 infection.