Pregnancy outcomes in Italy during COVID-19 pandemic: a population-based cohort study

Objective: To compare the estimates of preterm birth (PTB; 22–36 weeks' gestational age, GA) and stillbirth rates during COVID-19 pandemic in Italy with those recorded in the three previous years. Design: A population-based cohort study of live- and stillborn infants was conducted using data from Regional Health Systems and comparing the pandemic period (1 March 2020–31 March 2021, n = 362 129) to an historical period (January 2017–February 2020, n = 1 117 172). The cohort covered 84.3% of the births in Italy. Methods: Poisson regressions were run in each Region and meta-analyses were performed centrally. We used an interrupted time series regression analysis to study the trend of preterm births from 2017 to 2021. Main outcome measures: The primary outcomes were PTB and stillbirths. Secondary outcomes were late PTB (32–36 weeks' GA), very PTB (<32 weeks' GA), and extremely PTB (<28 weeks' GA), overall and stratified into singleton and multiples. Results: The pandemic period compared with the historical one was associated with a reduced risk for PTB (risk ratio [RR] 0.91, 95% confidence interval [CI] 0.88–0.93), late PTB (RR 0.91, 95% CI 0.88–0.94), very PTB (RR 0.88, 95% CI 0.84–0.91) and extremely PTB (RR 0.88, 95% CI 0.82–0.95). In multiples, point estimates were not very different, but had wider CIs. No association was found for stillbirths (RR 1.01, 95% CI 0.90–1.13). A linear decreasing trend in PTB rate was present in the historical period, with a further reduction after the lockdown. Conclusions: We demonstrated a decrease in PTB rate after the introduction of COVID-19 restriction measures, without an increase in stillbirths.