Subsequent pregnancy after stillbirth: obstetrical and medical risks

Objective: To evaluate obstetric outcome after stillbirth according to placental and prothrombotic risk factors. Methods: Obstetric outcomes of women with prior stillbirth and subsequent pregnancies were reviewed. Data on the immediate subsequent pregnancy included fetal loss, stillbirth, obstetric/medical complications, gestational age and birth weight at delivery, mode of delivery, thrombophilia, and prescribed medication. Placental stillbirth was defined as stillbirth associated with placental abruption, intrauterine growth restriction (IUGR), or histological evidence of placental infarcts. Controls were unselected women who gave birth at our center during a single calendar year. Factors influencing recurrence risks were estimated. Results: Seventy-three subsequent pregnancies were identified. Five out of 73 (6.8%) women had a repeat stillbirth, significantly higher than controls (relative risk 22.2, 95% confidence interval 8.9-55.4). Four out of five repeat stillbirth cases occurred < 37 weeks gestation. Hypertensive complications, diabetes and abruption were higher, while gestational age and birth weight at delivery were significantly lower than controls. Prior placental stillbirth was associated with a 10.5 times higher risk of IUGR in the subsequent pregnancy compared with non-placental stillbirth. All five repeat stillbirth cases occurred in thrombophilic women. Conclusion: Women with prior stillbirth face an increased risk of pregnancy complications and stillbirth recurrence, especially with concurrent thrombophilia. Most repeat stillbirth cases occur preterm.