Estrogen May Trigger Blood Clots in Women with High Lp(a)
Whether elevated lipoprotein(a) (Lp[a]) levels cause dangerous blood clots in the veins (venous thromboemboli, or VTE) has not been determined, as study results have been inconsistent. Some researchers have felt that estrogen levels, which increase after menopause and with the use of oral contraceptives or menopausal hormone therapy (MHT), may interact with elevated Lp(a) to increase this risk. To test this theory, researchers turned to 55,302 premenopausal women, 129,045 postmenopausal women and 189,013 men with available baseline Lp(a) data in the UK Biobank. In these cohorts, 14%, 19% and 15%, respectively, had elevated Lp(a), defined as levels greater than or equal to 125 nanomols per liter [nmol/L]. Over a median of 13.6 years, 8,186 VTEs occurred. Elevated Lp(a) was found to be associated with VTE in premenopausal women and in postmenopausal women using hormone therapy, but not in other postmenopausal women or in men. This suggests that estrogen may mediate the association between Lp(a) and VTE (European Heart Journal, March 28, 2026).
