Limited Impact of COVID-19 on Pre-existing Trends in Postpartum Infection

To assess whether postpartum infection rates decreased among hospital deliveries during the pandemic.

We designed a pre-post pandemic comparison study of postpartum infection rates among hospital births in Québec, Canada between 2017 and 2022. We calculated postpartum infection rates per 10 000 deliveries and compared the prepandemic and pandemic periods using risk ratios (RRs) and 95% CIs from log-binomial multivariable regression models. We stratified the analysis by mode of delivery and adjusted the models for maternal age, parity, comorbidity, and socioeconomic deprivation. We used autoregressive interrupted time series analysis to verify whether the pandemic impacted pre-existing trends in postpartum infection rates.

Postpartum infections were less frequent during the pandemic. Among patients who underwent cesarean deliveries, there was a 30% reduction in the risk of postpartum infection during the pandemic compared with the prepandemic period (RR 0.70; 95% CI 0.62-0.79, P < 0.001). Among patients who underwent vaginal deliveries, there was a 12% reduction in risk (RR 0.88; 95% CI 0.81-0.97, P= 0.008). However, interrupted time series analysis indicated that the reduction in postpartum infections began as early as 2010 and that these pre-existing trends persisted during the pandemic.

Infection rates have decreased over time, especially among cesarean deliveries. The pandemic did not significantly alter the long-term trend in decreasing postpartum infection rates.