Introduction: To evaluate the pregnancy-associated risk of venous thromboembolism and the risk of stillbirth and miscarriage a multicenter, retrospective and controlled study was conducted in women carrying the homozygous factor V Leiden mutation and in an agematched control group of women from the normal population.
Patients and methods: In 64 homozygous (median age 44 years, range 21-75 years) and in 52 control women from five different centers data on venous thromboembolism and pregnancy outcome were obtained.
Results: The 64 homozygous women had in total 212 pregnancies, the 52 control women had 118 pregnancies. In homozygous women 65% of pregnancies ended with delivery of a viable infant, 15% with fetal loss (3.3% stillbirth, 12% miscarriage) and 20% by pregnancy termination. In the control women 75% of pregnancies ended with delivery of a viable infant, 12% with fetal loss (1.7% stillbirth, 10% miscarriage) and 13% by pregnancy termination. The differences were statistically not significant. Venous thromboembolism occurred significantly more often in the homozygous women, in 4.2% (9/212) during pregnancy and in 4.7% (10/212) after delivery or pregnancy termination. None of the control women had a thromboembolic episode.
Conclusion: Our data indicate that women with homozygous factor V Leiden have a high probability for a favorable pregnancy outcome. The increased risk for venous thromboembolism during pregnancy and after delivery would favor heparin prophylaxis during and after pregnancy in women homozygous for factor V Leiden.