Vaginal bromocriptine may ease pain and heavy bleeding in adenomyosis

By Tarun Sai LomteReviewed by Susha Cheriyedath, M.Sc.May 27 2026

In a small randomized trial, vaginal bromocriptine helped women with adenomyosis report less pain, lighter bleeding, shorter periods, and more regular cycles, pointing to a potential new treatment path that now needs broader confirmation.

Study: The impact of vaginal bromocriptine on reducing pain and menstrual bleeding in women with adenomyosis: a randomized controlled trial. Image Credit: Halfpoint / Shutterstock

In a recent study published in the journal Scientific Reports, researchers evaluated the impact of vaginal bromocriptine treatment in reducing menstrual bleeding, pain, and cycle irregularities among adenomyosis patients. The pilot randomized controlled trial compared bromocriptine monotherapy with routine treatment using oral contraceptive pills and mefenamic acid.

Adenomyosis imposes significant healthcare costs similar to chronic conditions like rheumatoid arthritis and diabetes. Current therapeutic options include progestins, gonadotropin-releasing hormone agonists, and oral contraceptives, which have modest efficacy and limited tolerability.

Given these limitations and quality-of-life impairments in patients with adenomyosis, there is a need for well-tolerated, effective therapies.

Evidence indicates that serum prolactin levels correlate with the progression of adenomyosis. As such, drugs targeting prolactin may represent a viable therapeutic strategy. Bromocriptine is a dopamine receptor agonist with potent activity that has been used to treat prolactinomas, hyperprolactinemia, acromegaly, Parkinson’s disease, pituitary adenomas, and some metabolic conditions like diabetes.

Prolonged use of bromocriptine is generally considered safe and has minimal renal, cardiac, hematologic, or hepatic toxicity. It is an inexpensive, well-tolerated, and accessible drug with a favorable safety profile.

Vaginal administration of bromocriptine has been shown to further increase tolerability by decreasing gastrointestinal reactions. Vaginal bromocriptine therapy is reported to effectively reduce serum prolactin in hyperprolactinemic individuals.

About the study

In the present study, researchers evaluated the efficacy of vaginal bromocriptine treatment on menstrual bleeding, pain, and cycle irregularities in adenomyosis patients. This randomized controlled trial was conducted in Iran during 2024-25.

Premenopausal females aged ≥ 25 years diagnosed with adenomyosis who presented with heavy menstrual bleeding were recruited. Participants required normal levels of serum prolactin and the use of adequate contraception.

Adenomyosis was diagnosed according to transvaginal ultrasound criteria: asymmetric myometrial wall thickness, myometrial cysts, fan-shaped acoustic shadowing, and an irregular endometrial-myometrial junction.

Individuals with ovarian or uterine malignancy, acute pelvic infection, endometriosis, and those using intrauterine devices, steroidal oral contraceptives, antidepressants, or opioid analgesics, among others, were excluded. Eligible participants were randomized to the bromocriptine and control groups.

The intervention group was initiated on once-daily 2.5 mg vaginal bromocriptine and switched to twice daily from the second week, whereas controls received mefenamic acid and oral contraceptive pills. The treatment duration was three months.

Participants completed follow-up visits during the proliferative phase of the third month, with a final evaluation after a subsequent one-month follow-up period. Pain intensity was assessed on the visual analog scale within three days, three to seven days, and after seven days of menstruation.

Menstrual blood loss was determined using a standardized pictorial blood loss assessment chart. The primary outcomes were changes in pain intensity and menstrual bleeding, assessed using the visual analog scale and the pictorial blood loss assessment chart, respectively. Menstrual cycle regularity was also evaluated as an important clinical outcome.

Menstrual blood loss was compared between groups using the Mann-Whitney U test and the independent-samples t-test. The paired t-test evaluated within-group comparisons. Linear regression models examined changes in menstrual bleeding, adjusting for potential confounders.

Findings

The study included 64 individuals with adenomyosis, 32 per group. All subjects completed the treatment and one-month post-treatment follow-up. On average, participants’ age, body mass index, and other demographic characteristics did not differ significantly between the intervention and control groups. Both groups also showed comparable baseline endometrial thickness, myometrial cyst count, uterine volume, and menstrual cycle length.

There were no differences in baseline menstrual bleeding volume or pain intensity between groups. The average pain score was significantly lower in bromocriptine recipients than in controls after the intervention. Menstrual bleeding volume was significantly lower post-treatment in the bromocriptine group relative to controls. The bromocriptine group also showed significantly shorter menstrual duration than controls.

Most bromocriptine recipients (75%) reported regular menstrual cycles post-treatment, while only one in four controls had regular cycles. Regression analysis revealed that bromocriptine significantly decreased menstrual bleeding relative to controls.

Of note, endometrial thickness and myometrial cysts were associated with elevated menstrual bleeding. Other variables, such as weight, age, uterine volume, and uterine wall thickening, were not associated with menstrual bleeding.

Conclusions

In summary, vaginal bromocriptine treatment resulted in a clinically meaningful and statistically significant decrease in menstrual bleeding and pain intensity. 

In addition, menstrual cycle regularity improved and menstrual duration decreased with bromocriptine. However, the intervention group received bromocriptine alone, whereas the control group received routine treatment with oral contraceptive pills and mefenamic acid, which may complicate direct attribution of all observed differences to bromocriptine. 

The study’s limitations include a short follow-up period, lack of comprehensive, long-term biochemical and imaging analyses, and reliance on subjective measures of pain intensity. 

Overall, these findings show that vaginal bromocriptine could be a promising, generally well-tolerated investigational treatment option for adenomyosis, although larger and longer trials are needed to confirm its efficacy and safety.

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