(525) Effects of Dutch tocolysis protocol adjustment for threatened preterm birth after 30 weeks of gestation.

In 2019, the Dutch protocol was adjusted to not administer tocolysis for threatened preterm birth (PTB) between 30 and 34 weeks of gestation, since its effect on improving perinatal outcome is unclear. Administration of corticosteroids for fetal lung maturation was unchanged. The aim of this study is to evaluate the adjustment by investigating neonatal outcomes between 30 and 32 weeks of gestation before and after the protocol change.

Study Design:

We performed a nationwide cohort study comparing outcomes of births in the years 2018 (before protocol change) and 2020 (after protocol change). Data was extracted from the national Perinatal Registry (PERINED). Women with a spontaneous PTB from 30⁺⁰ to 31⁺⁶ weeks of gestation were included. The primary outcome was a composite of mortality, severe intraventricular hemorrhage, severe necrotizing enterocolitis, cystic periventricular leukomalacia, and retinopathy of prematurity needing therapy. Secondary outcomes included additional neonatal outcomes.

Results:

We included 521 women with PTB. There was no significant difference in composite neonatal outcome of births in 2018 compared to 2020 (8.4% (18/215) vs 8.2% (25/306) respectively, Odds Ratio (OR) 0.97 (95% Confidence Interval (CI) 0.52-1.83)). No difference was found when analyzing the groups as singletons (7.1% (12/170) vs 9.3% (19/204), OR 1.35 (95% CI 0.64-2.9)), and multiples (13.3% (6/45) vs 5.9% (6/102), OR 0.41 (95% CI 0.12-1.3)).

Conclusion:

We found no significant difference in composite neonatal outcome in pregnancies resulting in spontaneous PTB between 30 and 32 weeks of gestation in 2018 (with tocolysis) compared to 2020 (no tocolysis). These results support the adjustment to not administer tocolytic treatment in women with threatened PTB between 30 and 32 weeks of gestation.