Danish premature birth rates during the COVID-19 lockdown

Abstract

To explore the impact of COVID-19 lockdown on premature birth rates in Denmark, a nationwide register-based prevalence proportion study was conducted on all 31 180 live singleton infants born in Denmark between 12 March and 14 April during 2015-2020.The distribution of gestational ages (GAs) was significantly different (p=0.004) during the lockdown period compared with the previous 5 years and was driven by a significantly lower rate of extremely premature children during the lockdown compared with the corresponding mean rate for the same dates in the previous years (OR 0.09, 95% CI 0.01 to 0.40, p<0.001). No significant difference between the lockdown and previous years was found for other GA categories.The reasons for this decrease are unclear. However, the lockdown has provided a unique opportunity to examine possible factors related to prematurity. Identification of possible causal mechanisms might stimulate changes in clinical practice.

Keywords: epidemiology; neonatology.

Figure 1

Proportion of extremely premature and very premature births (permille of all births in the time period) during the lockdown period (12 March–14 April 2020) compared with aggregated birth data for the previous 5 years during the same date range (12 March–14 April 2015–2019). Inset graph: a comparison of extremely premature and very premature births born between 20 January and 22 February 2020 and an aggregate from that date range for the previous 5 years (20 January–22 February 2015–2019). Extremely premature (before 28⁺⁰ weeks’ gestation) and very premature (28⁺⁰–31⁺⁶ weeks’ gestation). Error bars represent 95% CIs.