Factor V Leiden mutation and the risk of venous thromboembolism in pregnant women.
OBJECTIVE
In this retrospective, single center, cohort study we assessed the risk of pregnancy-related venous thromboembolism (VTE) in women belonging to a large number of families identified because of a symptomatic proband with single identified factor V Leiden mutation.


METHODS
Female family members who had experienced at least one full-term pregnancy were enrolled in the study. Two hundred and seventy pregnancies occurred in 105 carriers and 215 pregnancies in 81 non-carriers of factor V Leiden mutation.


RESULTS
The frequency of VTE was 6.4% for heterozygous, 16.7% for homozygous, 20% for double heterozygous carriers of thrombophilic defects, and 1.2% for non-carriers. The majority of VTE events related to pregnancy occurred in the post-partum period. The relative risks of developing pregnancy-related VTE in women who were carriers of heterozygous and homozygous (or combined heterozygous) factor V Leiden mutation as compared to non-carriers were 5.3 (95% CI, 0.6 to 43.9) and 15.4 (95% CI, 1.4 to 164), respectively.


CONCLUSIONS
Factor V Leiden mutation is a risk factor for pregnancy-related VTE, especially in its homozygous form and in combination with other thrombophilic abnormalities. Screening of families with this mutation might be useful for women of fertile age, as they may take advantage from thromboprophylaxis during pregnancy and the post-partum period.
Tormene
D
D
Department of Medical and Surgical Sciences, 2nd Chair of Internal Medicine, University of Padua Medical School, via Ospedale Civile 105, 35128 Padua, Italy.
Simioni
P
P
Prandoni
P
P
Luni
S
S
Zerbinati
P
P
Sartor
D
D
Franz
F
F
Girolami
A
A
D000328:Adult; D016022:Case-Control Studies; D015331:Cohort Studies; D005165:Factor V / Q000235:genetics*; D005192:Family Health; D005260:Female; D006801:Humans; D009154:Mutation; D011247:Pregnancy; D011250:Pregnancy Complications, Hematologic / Q000453:epidemiology*; D012189:Retrospective Studies; D012307:Risk Factors; D013923:Thromboembolism / Q000453:epidemiology / Q000235:genetics*; D020246:Venous Thrombosis / Q000453:epidemiology / Q000235:genetics*
C095381:factor V Leiden; D005165:Factor V