Primary habitual abortions are associated with high frequency of factor V Leiden mutation.

Objective: To analyze the prevalence of the mutation G1691A in factor V gene (Leiden mutation), of mutation C677T in the methylenetetrahydrofolate reductase (MTHFR) gene, and of polymorphism in G20210A in the prothrombin gene in women with recurrent abortions; further, to identify a subgroup at higher risk of being carriers of these mutations.

Design: Prospective case control evaluation.

Setting: University clinic.

Patient(s): Eighty-four women with 3 or more consecutive miscarriages were compared with 69 controls.

Intervention(s): None.

Main Outcome Measure(s): Polymerase chain reactions were performed to identify the mutations G1691A in factor V and C677T in MTHFR genes and the polymorphism G20210A in the prothrombin gene.

Result(s): In women with primary habitual abortions, 27.8% carried the Leiden mutation. No difference was observed in the prevalence of mutation C677T in the MTHFR gene or in polymorphism G20210A in the prothrombin gene.

Conclusion(s): The Leiden mutation may play a considerable role for women having primary recurrent abortions.