The risk of fetal loss in family members of probands with factor V Leiden mutation.
In order to investigate the risk of fetal loss in carriers of factor V Leiden who are family members of probands with this mutation, we performed a retrospective cohort study including 109 women who had been pregnant at least once and were family members of 61 probands with venous thromboembolism and a single identified factor V Leiden mutation. The rate of pregnancies ending in unexplained fetal loss, early miscarriage, late miscarriage or stillbirth in women with the factor V Leiden was compared with that of women with normal genotype. In the 65 women who were carriers of factor V Leiden 31 of the 191 pregnancies (16.2% per pregnancy) resulted in unexplained fetal loss, as compared to 13 of the 121 pregnancies (10.7% per pregnancy) in the 44 non-carriers (relative risk, 1.5; 95% CI, 0.8-3.2). After the first trimester of pregnancy, 25 pregnancies (13.1% per pregnancy) among carriers of factor V Leiden ended in fetal loss, as compared to 7 (5.8% per pregnancy) among females with normal genotype (relative risk, 2.3; 95% CI, 1.01 to 5.1). We conclude that carriers of factor V Leiden who are family members of probands with this mutation have a statistically significant and clinically important risk of late miscarriage or stillbirth. Studies addressing the benefit-to-risk ratio of adopting routinary thromboprophylactic measures following the first trimester of pregnancy in these women are strongly indicated.
Tormene
D
D
Department of Medical and Surgical Sciences, University of Padua Medical School, Italy.
Simioni
P
P
Prandoni
P
P
Luni
S
S
Innella
B
B
Sabbion
P
P
Girolami
A
A
D015331:Cohort Studies; D020964:Embryo Loss / Q000235:genetics*; D005165:Factor V / Q000235:genetics*; D005260:Female; D005327:Fetal Resorption / Q000235:genetics*; D006801:Humans; D009154:Mutation; D011247:Pregnancy; D012189:Retrospective Studies; D012306:Risk; D012307:Risk Factors
C095381:factor V Leiden; D005165:Factor V