Obesity and estrogen use may increase blood clot risk in menopause

Obesity and oestrogen-based medicines together raise blood clot risk in premenopausal women, research finds.

The study explains how these factors combine to amplify thrombotic risk (dangerous blood clots) and offers insight to improve care for people already at higher risk, including those with cancer.

Researchers found that thrombosis risk rises sharply in premenopausal women with obesity who take oestrogen-based medicines because Protein S, a natural anticoagulant that helps prevent harmful clots, is substantially reduced.

The work was led by scientists in the LSU Health New Orleans Department of Interdisciplinary Oncology, with the Department of Genetics, the LSU LCMC Health Cancer Center and national and international partners.

Hypercoagulability (a tendency to form clots) is a serious concern during cancer treatment.

The findings may guide monitoring and prevention for cancer patients who have obesity or use oestrogen-based medicines, including hormone therapy or some birth control pills.

Dr Rinku Majumder, professor of interdisciplinary oncology at LSU Health New Orleans, said: “This study gives us a clearer picture of how everyday factors like weight and hormone use can interact in ways that have real health consequences.

“For cancer patients especially, having this knowledge helps us protect them more effectively.”

The study highlights the need to address obesity in Louisiana and across the US.

Obesity increases the risk of several cancers, and this work outlines a mechanism by which it also heightens thrombotic risk in people taking oral contraceptives or hormone-replacement therapy for menopausal symptoms.