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+6weeks 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.