Factor V Leiden mutation: a treatable etiology for sporadic and recurrent pregnancy loss

Objective We hypothesized that the thrombophilic G1691A factor V Leiden (FVL) gene mutation was a common, significant, and treatable cause of sporadic and recurrent pregnancy loss (RPL). Design We compared the frequency of the FVL mutation in 141 women with ≥1 pregnancy and 1 sporadic pregnancy loss (308 live births, 141 pregnancy losses), 44 women with ≥1 pregnancy and ≥3 pregnancy losses (105 live births, 180 pregnancy losses), and 638 women with ≥1 live birth pregnancy and 0 pregnancy loss (1553 live births). Setting Outpatient Clinical Research Center. Patient(s) A total of 823 caucasian women with consecutive measures of the FVL mutation. Main Outcome Measure(s) We used polymerase chain reaction techniques to characterize the thrombophilic FVL G1691A gene mutation. Result(s) Of the 638 controls, 47 (7.4%) had FVL heterozygosity versus 16 heterozygous and 2 homozygous FVL cases (18/141, 12.8%) in 141 women with 1 sporadic pregnancy loss versus 9/44 RPL cases (20.5%, 8 heterozygous and 1 homozygous FVL). The FVL frequency in cases with 1 sporadic pregnancy loss (18/141, 12.8%) did not differ from RPL cases (9/44, 20.45%). Conclusion(s) After unexplained sporadic pregnancy loss, as well as after RPL, to provide the option to prospectively optimize subsequent live birth outcomes with low-molecular-weight heparin thromboprophylaxis, we suggest that measurements be done of the FVL mutation, a treatable etiology for sporadic pregnancy loss as well as for RPL.