From the article:
A large study of 70 928 menopausal women in France between 1992 and 2008 looked at whether hormone therapy increased the risk of gallbladder surgery (cholecystectomy) for complications of gallstones. In France, hormonal therapy is usually administered topically rather than orally. North America and the United Kingdom prefer oral hormone therapies.
“In this large French prospective cohort study, we found that the risk of cholecystectomy was increased among women exposed to oral estrogen regiments for menopausal hormone therapy, especially oral regimens without progestagen,” writes Dr. Antoine Racine, Institut national de la santé et de la recherche médicale (INSERM) and Université Paris Sud, with coauthors. “Other types of menopausal hormone therapy [skin patches or gels] were not associated with an increased risk of cholecystectomy.”