Obstetric implications of fetal inherited thrombophilia in thrombophilic women

The relationship between fetal thrombophilic polymorphism and adverse pregnancy outcomes is still unclear. The aim of this study is to evaluate if fetal thrombophilia may affect obstetric and perinatal outcomes in thrombophilic women.

From 2007 to 2011 all patients with a known inherited thrombophilic mutation consecutively admitted to our labor ward at ⩾25weeks of gestation with a singleton viable pregnancy were considered eligible for the purpose of the study. At the age of 1year, the infants were tested for inherited thrombophilic mutations. Patients were then divided into two groups according to the presence or absence of any neonatal mutation.

The following outcome variables were then compared between the two groups: gestational age at delivery, birth weight, incidence of hypertensive disorders of pregnancy and SGA neonates.

Overall, 67 pregnancies of 49 women were studied. Among them, the G20210A Prothrombin (32/67 or 47.7%) mutation and the Factor V Leiden mutation (31/67 or 46.3%) were the commonest findings, with a single patient presenting both. A thrombophilic mutation was found in 38 mother-infant pairs. The risk of all maternal and perinatal events including the incidence of hypertensive disorders disorders (5/29 or 17.2% vs 6/38 or 15.7% p=1.00) and of SGA neonates (3/29 or 10.3% vs 7/38 or 18.4%, p=0.49) was comparable between the two groups irrespective of the associated fetal thrombophilia.

Our data suggest that women with inherited thrombophilia carrying a thrombophilic fetus are not at increased risk of adverse pregnancy outcomes.