Jóhanna Gunnarsdóttir, Marianne Philibert, Mika Gissler, Karin Kallen, Kari Klungsøyr, Marzia Loghi, Alison Macfarlane, Luule Sakkeus, Vlad Tica and Jennifer Zeitlin
Introduction
Labor is increasingly being induced to shorten the time at risk in utero. Large differences in gestational age distribution have been described between European countries. The aim was to explore mortality rates in relation to the prevalence of early-term births, considered to reflect different rates of planned birth by induction or cesarean.
Methods
Aggregated data on births ≥ 37 weeks in 28 European countries from 2015 to 2020 was collected by Euro-Peristat using a common data protocol. The proportion of early-term birth defined by gestational age 37+0 to 38+6 was calculated for each country and three groups created based on terciles (high, medium and low). Random-effects meta-analysis of proportions was used to compare pooled estimates of stillbirth, perinatal and neonatal mortality rates between terciles.
Results
Early-term births ranged from 17.8% (Iceland) to 49.1% (Cyprus), with tercile thresholds of <21%, 21-27% and >27%. Post-term births were rare in countries where early-term births were common. The stillbirth rate ≥ 37 weeks was 1.28 per 1000 total births (95%CI: 1.13-1.46) in the lowest tercile of early-term births and 1.05 (95%CI: 0.95-1.16) in the highest (p=0.05). In contrast, the neonatal mortality rate was 0.53 per 1000 live births (95% CI:0.43-0.64) in the lowest tercile but 0.74 (95%CI: 0.50-1.10) in the highest (p=0.29), and perinatal mortality rate did not vary significantly by tercile (p=0.71).
Conclusion
The stillbirth rate was lowest in countries where early-term births were most common, but no difference was found in perinatal mortality rate.
