The risk of recurrent preterm birth after spontaneous preterm birth
between 16-28 weeks of gestation: A national observational cohort study
Abstract
Background: Previous spontaneous preterm birth (sPTB) is an
important risk factor for recurrent PTB, yet consensus on the lower
limit of PTB is lacking. This complicates the identification of patients
at risk for recurrent PTB. Objectives: To assess the risk of
recurrent preterm birth following spontaneous extreme PTB between 16
+0 - 27 +6 weeks and the association
with the interpregnancy interval. Design: A nationwide
retrospective cohort study. Setting: Data from the Perinatal
Registry of the Netherlands. Population: Nulliparous women with
a singleton pregnancy that ended in sPTB between 16 +0
and 27 +6 weeks of gestation without congenital
anomalies or antenatal death between 2010-2014 and had a subsequent
pregnancy in the 5 years following. Main outcome measures:
Recurrent preterm birth < 37 weeks. Results: 1011
women with linked pregnancies were included. The risk of PTB <
37 weeks with prior spontaneous birth between 16 +0-19
+6, 20 +0-23 +6,
and 24 +0-27 +6 weeks was
respectively 19.0%, 29.5% and 27.6%. The risk of subsequent PTB
< 24 weeks was 5.7%, 7.2% and 4.3%. A short interpregnancy
interval of 0-3 months was associated with increased odds for recurrent
PTB < 32 weeks (OR 2.3 95% CI 1.4-3.7) and PTB < 37
weeks (OR 1.8 95% CI 1.2-2.6). Conclusion: Patients with
previous sPTB from 16 weeks GA onwards are at high risk for recurrent
PTB and should be regarded as such in the consideration of preventive
measures to prevent recurrent adverse pregnancy outcomes.