Oral contraceptives and thrombosis

Area of Science:

• Pharmacology and Thrombosis Research
• Reproductive Health and Epidemiology

Background:

• Ongoing debate exists regarding the association between third-generation progestogens (desogestrel, gestodene, norgestimate) and an increased risk of venous thrombosis compared to second-generation progestogens (levonorgestrel, norethindrone).
• Previous research has explored alternative explanations for this observed association, including prescribing bias, inadequate adjustment for age, and insufficient accounting for oral contraceptive duration of use.

Purpose of the Study:

• To investigate a potential biological explanation for the observed higher risk of venous thrombosis associated with third-generation progestogen use.
• To assess whether third-generation progestogen users exhibit different levels of acquired activated protein C (APC) resistance compared to second-generation progestogen users.

Main Methods:

• Development of a novel method for measuring activated protein C (APC) resistance.
• Comparison of acquired APC resistance levels between users of third-generation and second-generation progestogen-containing oral contraceptives.

Main Results:

• Users of third-generation progestogen preparations demonstrated higher levels of acquired activated protein C (APC) resistance.
• This finding suggests a potential biological mechanism linking third-generation progestogens to an increased risk of thrombosis.

Conclusions:

• The study presents a potential biological explanation for the observed association between third-generation progestogens and increased venous thrombosis risk.
• The findings regarding acquired APC resistance require further confirmation through independent studies.