Case Report: GLP-1 Drug Dulaglutide Linked to Severe Vaginal Bleeding in a Perimenopausal Woman

What the researchers found

A 44-year-old perimenopausal woman with type 2 diabetes, who had previously been unable to tolerate metformin and semaglutide, experienced significant vaginal hemorrhage beginning one week after receiving her second dose of dulaglutide.

The bleeding was severe enough to cause a significant drop in hemoglobin concentration. Upon discontinuation of dulaglutide, the vaginal bleeding stopped, establishing a temporal relationship between the drug and the adverse event.

This represents a rare, previously unreported side effect of dulaglutide not identified during clinical trials.

Why it matters

With tens of millions of people now taking GLP-1 receptor agonists worldwide, rare side effects that weren't detected in clinical trials are increasingly being identified in the general population. This case underscores the importance of post-market surveillance and physician awareness of unusual adverse reactions, particularly as these drugs are prescribed to a broader range of patients than those studied in original trials.

How the study worked

Single-patient case report documenting the clinical course, temporal relationship between dulaglutide administration and symptom onset, resolution upon drug discontinuation, and the patient's medical history including prior intolerance to other diabetes medications.

What this study cannot tell us

This is a single case report, which is the weakest form of clinical evidence. Temporal association (drug started → bleeding occurred → drug stopped → bleeding resolved) suggests but does not prove causation. The patient was perimenopausal, a period when irregular bleeding is common regardless of medication. No rechallenge was performed to confirm the drug was the cause. Other potential causes of vaginal bleeding were not fully detailed in the abstract. A single case cannot establish incidence rates.

How to read the evidence

This is a single case report — the lowest level of clinical evidence. It can raise awareness of a potential adverse effect but cannot establish causation, incidence, or mechanism. Multiple similar reports or controlled studies would be needed to confirm this as a genuine drug side effect.

When this study was published

Published in 2023, this case report is from the period of rapid GLP-1 RA adoption. Additional cases may have been reported since then, potentially strengthening or weakening the association.

The bigger picture

GLP-1 receptor agonists are among the fastest-growing drug classes in medicine, expanding from diabetes to obesity and potentially cardiovascular protection. As prescribing increases, post-market surveillance becomes critical for identifying rare adverse effects that clinical trials — which typically include only thousands of carefully selected patients — may miss. This case joins a growing collection of unusual GLP-1 side effect reports that help build a more complete safety profile for this drug class.

Questions still open

• Is this side effect specific to dulaglutide or could it occur with other GLP-1 receptor agonists like semaglutide or liraglutide?
• Could GLP-1 receptor activation directly affect uterine blood vessels or endometrial tissue, or was this an idiosyncratic reaction?
• Should perimenopausal women starting GLP-1 agonists be counseled about the possibility of abnormal bleeding?

Common questions

Read the original research

A Case of Dulaglutide-Induced Vaginal Bleed.

Cureus, 15(5), e38774

Citation

Vaccaro, Christopher J; Zaidi, Syed Muhammad Hussain; Iskander, Peter A; McFadden, Erin. (2023). A Case of Dulaglutide-Induced Vaginal Bleed.. Cureus, 15(5), e38774. https://doi.org/10.7759/cureus.38774