Preterm birth during the COVID-19 pandemic: more, less, or just the same?

Objectives Coronavirus disease (COVID-19) and its mitigation measures have been associated with changes in preterm birth (PTB) incidences. The objective of this paper is to summarize and comment on the literature on COVID-19 and PTB and to compare PTB incidence between 2019 (pre-COVID-19) and 2020 (COVID-19) in three Belgian tertiary care hospitals. Methods A non-systematic review on COVID-19 and PTB was performed, and literature was summarized in a table. Preterm birth rates at Ghent University Hospital, Ziekenhuis Oost-Limburg, and University Hospital Leuven in 2019 and 2020 were compared. Chi-square and Fisher's exact tests were used to compare PTB rates between 2019 and 2020, and Kaplan Meier survival analysis was used to compare pregnancy duration. The mean outcome measure was PTB incidence in 2020 (COVID-19) compared with PTB incidence in 2019 (pre-COVID-19). Results Some (parts of) countries report decreases in PTB rates, others report no differences in incidence, and a minority of countries report an increased incidence of PTB. Almost all studies only consider live-births. In three tertiary care hospitals in Flanders, there were no differences in PTB rates before and during the COVID-19 pandemic. Conclusion The impact of the (mitigation measures during the) COVID-19 pandemic on PTB incidence is unclear and difficult to explore. To enable a correct interpretation, all conceptions before and during the pandemic should be taken into consideration, as well as all births, still or alive.