Factor V Leiden mutation and pregnancy-related complications

OBJECTIVE: The objective of the study was to determine the prevalence of the factor V Leiden (FVL) mutation and its association with obstetric complications, blood loss during delivery, and venous thromboembolism (VTE). STUDY DESIGN: This was a prospective, observational, case-cohort study of 491 FVL carriers and 1055 controls derived from 6003 screened women. Data were analyzed with a Student t test and cross-tabulation. RESULTS: FVL carriership prevalence was 8.3%. Gestational age at delivery, birthweight deviation, gestational hypertension, and preeclampsia incidences did not differ between groups. The incidences of placental abruption, neonatal asphyxia, eclampsia, intrauterine fetal death, intrapartum death, and unexplained late miscarriage were low. The incidence of major blood loss at delivery was lower in carriers. There were 3 VTEs among carriers and none among controls. CONCLUSION: FVL carriership did not influence pregnancy-induced hypertension, birthweight, or prematurity but raised the risk of venous thromboembolism and lowered the risk of major blood loss.