Impact of COVID-19 pandemic on preterm delivery.

Objective: Controversies exist on whether the pandemic lockdown has resulted in a lower rate of preterm deliveries. A higher stillbirth rate was also reported. This retrospective observational study aimed to examine the rate of preterm delivery and stillbirth in a tertiary hospital in Hong Kong during COVID-19 pandemic.

Methods: Data from 8787 singleton pregnancies at Queen Mary Hospital between April 2018 to September 2021 were retrieved from the clinical management system and obstetric database. Rates of preterm delivery (<37 weeks), low birth weight infants (<2500 g), and stillbirth in the pre-pandemic (April 2018 to September 2019) and pandemic (April 2020 to September 2021) periods were compared.

Results: Total numbers of singleton deliveries during the pre-pandemic and pandemic periods were 5064 and 3723, respectively. Background demographics were comparable, except 3 were higher rates of cesarean sections (30.7% vs. 25.8%; p < 0.05) and hypertensive disorders (1.4% vs. 0.7%; p < 0.05) in the pandemic cohort. Moreover, more women with a spontaneous onset of labor had a history of preterm delivery (3.5% vs. 2.4%; p < 0.05) during the pandemic. Rates of low birth weight infants (8.7% vs. 7.4%; p = 0.03) and spontaneous preterm deliveries (2.6% vs. 1.7%; p = 0.01), particularly spontaneous moderate-to-late preterm delivery (32-36 weeks) (1.9% vs. 1.2%; p = 0.01) were significantly higher during COVID-19. However, no statistical difference was found in stillbirth rates (0.2% vs. 0.4%; p = 0.17).

Conclusions: Rates of spontaneous preterm delivery and low birth weight babies increased significantly during the COVID-19 pandemic. This could be related to an increase in maternal stress, or a change in behavioral patterns for pregnant women.