Stillbirth and Preterm Birth During Lockdown Periods in 5 Waves of COVID-19 Pandemic in Northern Iran: A Region-Wide Cohort Study in Mazandaran Province.

Introduction: Conflicting reports for preterm birth and stillbirth during the lockdown imposed during the COVID-19 pandemic have emerged. Most of the studies are related to the initial waves of the pandemic.

Objectives: This study aims to evaluate changes in preterm birth and stillbirth rates during various waves of COVID-19 in northern Iran.

Methods: This is a retrospective cohort study to evaluate preterm birth and stillbirth rate based on weight distribution per 1000 live births during lockdown periods in 5 peaks of the COVID-19 pandemic using the regional data registration system at Mazandaran University of Medical Sciences in northern Iran. We compared these rates with the corresponding months 4 years before the pandemic. The odds ratio for the primary outcome was estimated by logistic regression.

Results: We observed an overall increased rate of preterm birth during the pandemic compared to the pre-pandemic period (4.7% vs 2.8%, P < .001). The overall stillbirth rate increased during the COVID-19 pandemic compared to the pre-pandemic period (7.48/1000 vs 5.41/1000, odds ratio: 1.38 [1.21-1.57]). This increase in the rate of stillbirth was significantly observed in the fifth wave of the COVID-19 pandemic (P < .001).

Conclusion: Our study showed that adverse pregnancy outcomes increased during lockdown periods of a global pandemic. Further studies from geographically diverse regions to evaluate different behavior changes during pregnancy and access to prenatal services, and its impact on pregnancy outcomes is recommended.