COVID-19 mitigation measures increase preterm birth and low birth weight in the public healthcare system in Uruguay.

OBJECTIVE To evaluate the impact of the COVID-19 pandemic on preterm birth (PB) and low birth weight (LBW), comparing public and private healthcare systems of the National Integrated Health System in Uruguay, where the mitigation measures for the COVID-19 pandemic generated an immediate socioeconomic and psychological crisis, which caused a sharp widening of existing socioeconomic inequalities. METHODS A national observational study was conducted comparing perinatal outcomes in the first 6 months of 2020 (period of the pandemic without pregnancy infections), which was the beginning of the pandemic, with the same period of the previous year 2019 (pre-pandemic period with no mitigation measures) among pregnant women from the public and private health systems. Data were retrieved from the national database (Informatic Perinatal System) and analyzed by healthcare system category. RESULTS A total of 36 559 deliveries were assessed: 18 563 in the 2019 study period and 17 996 in the 2020 study period. In the public system, there was a significant increase in the risk of LBW (adjusted relative risk [aRR] 1.12, 95% confidence interval [CI] 1.05-1.36) and of the composite outcome (PB or LBW) (aRR 1.15, 95% CI 1.04-1.26). In the private system, by contrast, there was a non-statistically significant decrease of LBW and there were no changes in the incidence of PB and the composite outcome in 2020. CONCLUSION The different evolution of birth outcomes in the public and private systems suggests an unequal impact of mitigation measures on populations of different socioeconomic levels. Given that no COVID-19 infections were identified in pregnant women during the study period, this research offers an opportunity to differentiate the biologic effects of the virus from the psychological and social impacts derived from containment measures. CLINICALTRIALS GOV IDENTIFIER NCT05087160.