Screening women for oral contraception: can family history identify inherited thrombophilias?

Objective: Screening for inherited thrombophilias with laboratory tests is impractical before starting women on combined oral contraceptives. As an alternative, some recommend eliciting a family history of venous thromboembolism. The validity of this approach, however, remains unclear.

Data Sources: We sought all published reports that correlated a family history of venous thromboembolism with any thrombophilia confirmed by laboratory test. We used sequential, overlapping computer searches including MeSH terms used for articles in PubMed, a narrative search phrase in Google Scholar, and then all "related" articles in PubMed for each article included without time or language limitations. This was supplemented by a search of www.clinicaltrials.gov.

Methods Of Study Selection: The search yielded 10 reports. Information was sought without success from corresponding authors of four other reports that may have had relevant data. Most reports studied atypical, high-prevalence referral populations.

Tabulation, Integration, And Results: Results were presented according to the MOOSE (Meta-analysis of observational studies in epidemiology) guidelines for systematic reviews of observational studies. The patient populations varied widely, definitions of family history included first- or first- and second-degree relatives, and the thrombophilias studied differed among these reports. Hence, aggregation of results was not possible. Despite these differences, all reports consistently documented poor validity of family history for detecting thrombophilias. Sensitivity ranged from 16% to 63% and positive predictive value from 6% to 50% for the various thrombophilias studied. In no study did family history meet the benchmark for a good test (sensitivity plus specificity greater than 150%).

Conclusion: Obtaining a family history of venous thromboembolism before starting combined oral contraceptives is not a valid means to detect a woman's risk of thrombophilia. Even in high-prevalence populations, in which the positive predictive value is increased, a positive family history of venous thromboembolism was no better than flipping a coin in predicting thrombophilia.