Risk of thrombosis associated with oral contraceptives of women from 97 families with inherited thrombophilia: high risk of thrombosis in carriers of the G20210A mutation of the prothrombin gene.
OBJECTIVE
Oral contraceptives (OC) and inherited thrombophilia are well-known risk factors associated with venous thromboembolism (VTE). However, there are only few studies on the risk of VTE in women with inherited thrombophilia who use oral contraceptives.


METHODS
We performed a retrospective family cohort study of 325 women belonging to 97 families with inherited thrombophilia, including antithrombin, protein S and C deficiencies, the factor V Leiden mutation (FVL) and the G20210A mutation of the prothrombin gene (PT20210A) to determine the risk of VTE associated with OC intake.


RESULTS
For carriers of the PT20210A mutation, the risk of VTE in OC users was 3-fold higher (95% CI 1.3-6.8) than that in non-carriers. Carriers of FVL mutation taking OC showed an OR of 1.4 (95% CI 0.6-3.3), indicating a tendency to increase the risk of VTE.


CONCLUSIONS
Because of the high prevalence of the PT20210A (6.5%) and FVL (2%) mutations in the general Spanish population and the increased risk of VTE associated with OC intake, genetic screening for these mutations should be considered in potential OC users belonging to families with thrombophilia.
Santamaría
A
A
Thrombosis and Haemostasis Unit, Haematology Department, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain.
Mateo
J
J
Oliver
A
A
Menéndez
B
B
Souto
J C
JC
Borrell
M
M
Soria
J M
JM
Tirado
I
I
Fontcuberta
J
J
D000293:Adolescent; D000328:Adult; D015331:Cohort Studies; D003276:Contraceptives, Oral / Q000009:adverse effects*; D005192:Family Health; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008875:Middle Aged; D012189:Retrospective Studies; D018570:Risk Assessment; D013030:Spain / Q000453:epidemiology; D019851:Thrombophilia / Q000150:complications / Q000235:genetics*; D013927:Thrombosis / Q000139:chemically induced* / Q000209:etiology / Q000235:genetics
D003276:Contraceptives, Oral