Women taking menopause hormone therapy in pill form had higher rates of blood clots in the legs and lungs than women not using hormones, according to a large Danish study published this week in The BMJ. The link held at every dose and treatment length the researchers examined. Women using patches, gels, or sprays showed no general increase in clot risk.
The findings matter for the many U.S. women in their 50s and 60s weighing treatment for hot flashes, night sweats, and poor sleep. The extra risk was small in absolute terms, and the study was observational, so it shows an association rather than proof that the pills caused the clots. Still, it gives women and clinicians sharper detail on a practical question: whether the way estrogen enters the body changes the risk.
