A Danish national cohort study on neonatal outcome in singleton pregnancies with placenta previa

To describe the incidence of placenta previa and to assess neonatal morbidity and mortality in pregnancies with placenta previa after adjustment for previous cesarean section, smoking, multiparity, maternal age and in vitro fertilization.

National cohort study.

Danish national IVF-, birth- and patient registers.

All pregnancies in Denmark from 1978-2006 and a subpopulation of all singleton pregnancies during the years 2001-2006 with placenta previa (n=1721) compared to pregnancies without this diagnosis.

Incidence rates and multivariate analysis.

Gestational age, birthweight, Apgar score after five minutes, stillbirth, neonatal mortality and admittance to neonatal intensive care unit.

The incidence of placenta previa in Denmark was 0.54% in 2006. Neonates born after pregnancies with placenta previa had a higher risk of being born at a gestational age below 37 weeks (OR 8.6; 95%CI 7.5-9.9), having an Apgar score of ≤7 at five minutes (OR 2.7; 95%CI 2.0-3.7), being transferred to a neonatal intensive care unit (OR 4.3; 95%CI 3.8-4.9) and for stillbirth and neonatal mortality combined (OR 1.8; 95%CI 1.1-3.0), compared with neonates born in pregnancies without placenta previa. No increased risk of being small-for-gestational age was found (OR 1.0; 95%CI 1.0-1.2).

When adjusting for confounders, neonates born after pregnancies with placenta previa had a significantly higher risk of being born preterm, having a low Apgar score, being transferred to neonatal intensive care, and death.