Semaglutide Linked to Menstrual Changes Including Heavy Bleeding
核心洞察
A new analysis of FDA Adverse Event Reporting System (搜索) reports found disproportionate menstrual event reporting with semaglutide, including heavy bleeding, intermenstrual bleeding, clots, oligomenorrhea (搜索) and anovulatory cycles (搜索).
Tirzepatide showed significant signals only for intermenstrual bleeding and menstrual clots, while liraglutide produced no significant menstrual-event signals in the same analysis.
Researchers examined reports for female patients ages 12 to 55 using disproportionality and Bayesian methods, and the findings do not establish that any GLP-1 drug caused the menstrual changes.
An analysis of reports submitted to the FDA Adverse Event Reporting System (搜索) (FAERS) has identified several menstrual events reported disproportionately often with semaglutide, including heavy menstrual bleeding, intermenstrual bleeding, menstrual blood clots, oligomenorrhea (搜索) and anovulatory cycles (搜索). The researchers examined reports involving female patients ages 12 through 55, using FAERS data available through March 2026, and focused on semaglutide, tirzepatide and liraglutide. Rather than counting reports, they applied disproportionality and Bayesian analyses to detect events reported more frequently with a given drug than expected from reporting patterns elsewhere in the database.
The signal pattern differed across the three drugs. Tirzepatide produced significant signals for intermenstrual bleeding and menstrual clots but not the broader range seen with semaglutide, while liraglutide showed no significant menstrual-event signals. The researchers note that GLP-1 medications act on related metabolic pathways but are distinct drugs, and tirzepatide targets both GLP-1 and GIP receptors whereas semaglutide targets the GLP-1 receptor (搜索). The study was not designed to determine whether those pharmacological differences explain the divergent reporting patterns.
The findings do not establish causation. FAERS is a spontaneous reporting database with no reliable denominator, so true incidence among users cannot be calculated, and reporting is influenced by media coverage, awareness, prescribing patterns and underreporting. Obesity (搜索), PCOS, diabetes and rapid weight or metabolic changes can themselves affect menstrual cycles, and weight loss or improved insulin sensitivity may either regularize or disrupt cycles depending on the patient. The anovulatory-cycle signal raises fertility questions, but the analysis cannot show that semaglutide suppresses ovulation or reduces fertility. The authors suggest menstrual health may warrant greater attention in counseling reproductive-aged patients on GLP-1 medications and call for prospective research.