Objective: To investigate the trend in preterm birth (PTB) rates and the influence of several potential maternal risk factors on PTB in Italy from January 2018 to December 2022, before and after COVID-19 pandemic. Design: Population-based study covering 86.11% of all Italian births. Methods: We conducted an interrupted time series analysis to examine the PTB trend. Using Poisson regressions, we assessed the associations (risk ratio, RR) of potential risk factors with PTB and calculated their population impact fractions (PIFs). Main outcome measures: Primary outcomes included the temporal trends of PTB rates before and after the pandemic, and the change during the pandemic. Secondary outcomes involved the associations of potential risk factors with PTB rates, and PIFs. Results: We observed a monthly decrease in PTB rate until July 2020 [-0.2% (95% CI: -0.3; -0.1)], followed by an interruption with an abrupt drop of -5% in July 2020 (95% CI: -7.3; -2.7). From August 2020 until December 2022 the trend remained flat (-0.02%, 95% CI: -0.5; 0.5). Among studied risk factors, low maternal education, unemployment and foreign nationality were associated with PTB [RR: 1.14 (95% CI: 1.04;1.24), 1.08 (1.05;1.12), and 1.17 (1.14;1.21), respectively], and showed a decreasing trend after pandemics; the impact (PIFs) on PTB rates was modest with a decrease between 2.4 and 4.2‰ PTB. Conclusions: We confirmed a decrease in PTB rates before and during the pandemic described also in other European countries. In Italy, post-pandemic PTB trend remained flat. Socioeconomic risk factors for PTB only marginally explained this pattern. Tweetable abstract In Italy, the decrease in preterm births before and during COVID-19 stopped after the pandemic; the impact of socio-economic disparities was minimal

A document by Franca Rusconi. Click on the document to view its contents.

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 liveborn and stillborn infants was conducted using data from Regional Health Systems and comparing the pandemic period (March 1st, 2020-March 31st, 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. Logistic 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 extreme 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 (Odds Ratio: 0.90; 95% Confidence Interval, CI: 0.87, 0.93), late PTB (0.91; 0.87, 0.94), very PTB (0.87; 0.84, 0.91), and extreme PTB (0.88; 0.82, 0.94). In multiples, point estimates were not very different, but had wider CIs. No association was found for stillbirths (1.01; 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.