Clot Risk High With Oral Contraceptives for Those at Genetic Risk

FRIDAY, Dec. 1, 2023 (HealthDay News) -- Oral contraceptive (OC) use is associated with an increased risk for developing a venous thromboembolism (VTE), particularly among women with a high genetic predisposition, according to a study recently published online in the American Journal of Obstetrics & Gynecology.

Valeria Lo Faro, Ph.D., from Uppsala University in Sweden, and colleagues estimated the risk for developing VTE when initiating OC use (first two years) and during continued use among women with a high genetic liability. The analysis included 244,420 participants in the U.K. Biobank.

The researchers found that overall, there was an increased risk for VTE during the first two years of OC use (hazard ratio [HR], 3.09; 95 percent confidence interval [CI], 3.00 to 3.20) but not during continued use (HR, 0.92; 95 percent CI, 0.80 to 1.05). When considering genetic risk, women in the highest polygenic risk score group had a more pronounced risk for VTE during the first two years of OC use. Similarly, high risk was seen among factor V Leiden and prothrombin variant carriers. The combination of a high polygenic risk score and being a factor V Leiden and prothrombin variant carrier conferred the highest risk for developing a VTE during the first two years of OC use (HR, 14.8; 95 percent CI, 9.28 to 23.6). During continued use, women with a high genetic liability also had increased VTE risk, but it was less pronounced.

"This is important knowledge for women’s health and may be important in contraception counselling," Lo Faro said in a statement.

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