Recurrence risk of low Apgar score among term singletons: a population-based cohort study.

Objective: To examine the risk of recurrence of low Apgar score in a subsequent term singleton pregnancy.
Design: Population-based cohort study.
Setting: The Netherlands.
Population: A total of 190,725 women with two subsequent singleton term live births between 1999 and 2007.
Methods: We calculated the recurrence risk of low Apgar score after adjustment for possible confounders. Women with an elective cesarean delivery, fetus in breech presentation or a fetus with congenital anomalies were excluded. Results were reported separately for women with a vaginal delivery or a cesarean delivery at first pregnancy.
Main Outcome Measures: Prevalence of birth asphyxia, a 5-min Apgar score <7.
Results: The risk for an Apgar score of <7 in the first pregnancy was 0.99% and overall halved in the subsequent pregnancies (0.50%). For those with asphyxia in the first pregnancy, the risk of recurrence of a low Apgar score in the subsequent pregnancy was 1.1% (odds ratio 2.1, 95% confidence interval 1.4-3.3). This recurrence risk was present in women with a previous vaginal delivery (odds ratio 2.1, 95% confidence interval 1.2-3.5) and in women with a previous cesarean delivery (odds ratio 3.8, 95% confidence interval 1.7-8.5). Among women with a small-for-gestational-age infant in the subsequent pregnancy and a previous vaginal delivery, the recurrence risk was 4.8% (adjusted odds ratio 5.8, 95% confidence interval 2.0-16.5).
Conclusion: Women with birth asphyxia of the first born have twice the risk of renewed asphyxia at the next birth compared to women without birth asphyxia of the first born. This should be incorporated in the risk assessment of pregnant women.
(© 2014 Nordic Federation of Societies of Obstetrics and Gynecology.)