The paradoxical influence of the COVID-19 lockdown period on different types of preterm births in Alberta: a provincial study.

Objectives: The objective of this study was to determine if the COVID-19 pandemic impacted different types of preterm birth rates in Alberta, Canada.

Methods: A population-based, retrospective, cohort study was conducted from March 15, 2015 to December 31, 2020 using provincial data. The primary exposure was the COVID-19 lockdown period, and the primary outcome was the incidence of preterm birth (<37 weeks gestational age). Multivariable analyses in the complete lockdown and overall lockdown (partial and complete lockdown) periods were performed to test the association between the year of birth and preterm birth status and were adjusted for various independent variables. Preterm birth status was adjusted for various confounding factors.

Results: Following the analysis of n = 41,187 mothers and their singleton infants, we found that the lockdown due to COVID-19 had no impact in reducing the overall preterm birth rate. However, a paradoxical influence was observed with an increase of extremely low preterm births in the overall lockdown period, and a decrease in moderate preterm births during the complete lockdown period.

Conclusions: The results of this study demonstrated that there was a decrease in moderate and increase in extremely low preterm birth rates as a result of the COVID-19 lockdown. However, the COVID-19 lockdown did not impact the very preterm and late preterm birth rate in Alberta.