COVID-19 lockdown and association with placental function – a quasi-experimental analysis

OBJECTIVE: To evaluate the effect of COVID-19 lockdown measures on the occurrence of hypertensive disorders of pregnancy and fetal growth restriction in a national pregnancy population. STUDY DESIGN: This is a national registry-based quasi-experimental study, including singleton births ≥24 + 0 weeks from nulliparous women between 2016-2020. We evaluated the effect of gestational age upon entering the first nationwide lockdown period (March 9th-June 1st 2020) on outcome. This effect can be assumed to be unconfounded (a so-called quasi-experimental analysis), because this period was unexpected and implemented rapidly, minimizing anticipatory changes at population level. MAIN OUTCOME MEASURES: Primary outcomes were hypertensive disorders of pregnancy (including pre-eclampsia) and small-for-gestational-age (birthweight