Clotting factors after emergency contraception

Area of Science:

• Reproductive endocrinology
• Thrombosis research
• Pharmacology

Background:

• Women with a history of thromboembolic disease are often contraindicated for oral emergency contraception due to theoretical thrombosis risks.
• Previous concerns have limited contraceptive options for this patient population.

Purpose of the Study:

• To investigate the effect of standard Yuzpe regimen emergency contraception on clotting factors in healthy women.
• To assess the safety of ethinylestradiol and levonorgestrel in women with potential thrombophilia.

Main Methods:

• Eleven healthy female volunteers with regular menstrual cycles were enrolled.
• Clotting factors (Factor VII and antithrombin III) were measured over three cycles, including a cycle with emergency contraception administration.
• Blood samples were collected at multiple time points before and after emergency contraception to monitor factor levels.

Main Results:

• Significant inter- and intra-subject variability in clotting factors was observed during the study.
• No discernible impact on measured clotting factor levels was detected following the administration of emergency contraception.
• The effects, if any, on clotting factors were transient and not evident in follow-up measurements.

Conclusions:

• The short-term administration of ethinylestradiol in emergency contraception does not appear to alter key clotting factors.
• These findings challenge the automatic contraindication of ethinylestradiol-based emergency contraception in women with a history of thromboembolic disease.
• Further research may support reconsidering contraceptive guidelines for this demographic.