Thrombophilic risk factors for placental stillbirth.

OBJECTIVES

To define the characteristics of placental stillbirth and the possible contribution of thrombophilic risk factors.

STUDY

DESIGN

A prospective cohort study was performed. Women diagnosed with antenatal stillbirth (>20 weeks) of singleton pregnancies between 2006 and 2008 were referred postpartum for evaluation. Maternal risk factors, fetal, placental and cord abnormalities, and a detailed thrombophilia screening, including inherited and acquired thrombophilia, were evaluated. Fetal autopsy and placental pathology were encouraged. Placental stillbirth was defined as death of a normally-formed fetus with evidence of intrauterine fetal growth restriction, oligohydramnios, placental abruption and/or histological evidence of placental contribution to fetal death. Pregnancy characteristics and thrombophilia profiles were compared between placental and non-placental stillbirth cases.

RESULTS

Sixty-seven women with stillbirth comprised the study group. Placental stillbirth was evident in 33/67 (49.3%). Significantly more women with placental stillbirth were nulliparous, when compared with non-placental stillbirth women (21/33 vs. 9/34, p=0.002). Mean gestational age was lower for placental, compared with non-placental stillbirth (31.1 ± 6.1 weeks vs. 33.9 ± 4.8 weeks, p=0.04), as was birth weight. Thirty-six of the 67 women (53.7%) tested positive for at least one thrombophilia. The prevalence of maternal thrombophilia was higher for placental stillbirth women (63.6%), and even higher (69.6%) for women after preterm (<37 weeks) placental stillbirth. Factor V Leiden and/or prothrombin G20210A mutation were much more prevalent in placental versus non-placental stillbirth women (OR 3.06, 95% CI 1.07-8.7).

CONCLUSIONS

Placental stillbirth comprises a unique subgroup with specific maternal characteristics. Maternal thrombophilia is highly prevalent, especially in preterm placental stillbirth. This may have implications for the management strategy in future pregnancies in this subgroup.