(272) Trends in preterm birth in the Netherlands in 2011–2019: a population-based study

Based on the national perinatal registry, we included all pregnancies without severe congenital abnormalities resulting in a birth from 24 to 42 completed weeks of gestation between 2011 and 2019 in the Netherlands. We assessed preterm birth rates in 2 different subtypes (spontaneous versus iatrogenic) and in 4 gestational age subgroups: 24–27⁺⁶ weeks, 28–31⁺⁶ weeks, 32–36⁺⁶ weeks and < 37w weeks. Trend analysis was performed using the Cochran Armitage test. We also compared PTB rates in different subgroups in the first two years compared to the last two years. Singleton and multiple gestations were analyzed separately.

Results:

We included 1,447,689 singelton and 23,250 multiple pregnancies in our study. In singletons, we observed a significant decline in PTB from 5.5% in 2011 to 5.0% in 2019 (p< 0.0001), mainly due to an decrease in iatrogenic preterm births, fig 1. When assessing PTB risk in different subgroups, the decline was not visible in women with age < 25 years, a low socioeconomic status or with Mediterranean ethnicity (mainly Turkish, Moroccan). In multiples, the rate of preterm birth remained fairly stable, from 52.3% in 2011 to 54.1% in 2019 (p=0.57).

Conclusion:

The decline in PTB rate in the Netherlands compares favourably to other countries in which stable PTB rates or even increases in PTB rates are present. This suggests that implementation of effective preventive strategies have the potential to lead to a decrease in PTB rates. Focus for the near future should be on specific subgroups in which the decline was not visible.