Danazol is an effective treatment for the reduction of heavy menstrual bleeding, but the adverse effects may be unacceptable to women

Options to help avoid surgery can be important for many women who are having problems with heavy menstrual bleeding. One of the drug options is Danazol. Danazol suppresses the hormones that increase the endometrium (the lining of the uterus that is shed during menstruation). However, Danazol can also produce male characteristics and some menopause-like symptoms, as well as weight gain and acne. The review found that although Danazol is effective at reducing menstrual blood loss there are not enough trials to show whether this treatment is acceptable to women with heavy menstrual bleeding.

Authors' conclusions: 

Danazol appears to be an effective treatment for heavy menstrual bleeding compared to other medical treatments. The use of Danazol may be limited by its side effect profile, its acceptability to women and the need for continuing treatment. The small number of trials, and the small sample sizes of the included trials limit the recommendations for clinical care. Further studies are unlikely in the future and this review will not be updated unless further studies are identified.

Read the full abstract...

Heavy menstrual bleeding (HMB) is an important cause of ill health in pre menopausal women. Medical therapy, with the avoidance of possibly unnecessary surgery is an attractive treatment option, but there is considerable variation in practice and uncertainty about the most effective therapy. Danazol is a synthetic steroid with anti-oestrogenic and anti progestogenic activity, and weak androgenic properties. Danazol suppresses oestrogen and progesterone receptors in the endometrium, leading to endometrial atrophy (thinning of the lining of the uterus) and reduced menstrual loss and to amenorrhoea in some women.


To determine the effectiveness and tolerability of Danazol when used for heavy menstrual bleeding in women of reproductive years.

Search strategy: 

We searched the Menstrual Disorders and Subfertility Group's Specialised Register (April 2007). We also searched the Cochrane Controlled Trials Register (Cochrane Library, Issue 2, 2007), MEDLINE (1966 to April 2007), EMBASE (1980 to April 2007, CINAHL (1982 to April 2007). Attempts were also made to identify trials from citation lists of included trials and relevant review articles.

Selection criteria: 

Randomised controlled trials of Danazol versus placebo, any other medical (non-surgical) therapy or Danazol in different dosages for heavy menstrual bleeding in women of reproductive age with regular HMB measured either subjectively or objectively. Trials that included women with post menopausal bleeding, intermenstrual bleeding and pathological causes of heavy menstrual bleeding were excluded.

Data collection and analysis: 

Nine RCTs, with 353 women, were identified that fulfilled the inclusion criteria. Quality assessment and data extraction were performed independently by two reviewers. The main outcomes were menstrual blood loss, the number of women experiencing adverse effects, weight gain, withdrawals due to adverse effects and dysmenorrhoea. If data could not be extracted in a form suitable for meta-analysis, they were presented in a descriptive format.

Main results: 

Most data were not in a form suitable for meta analysis, and the results are based on a small number of trials, all of which are under-powered. Danazol appears to be more effective than placebo, progestogens, NSAIDs and the OCP at reducing MBL, but confidence intervals were wide. Treatment with Danazol caused more adverse events than NSAIDs (OR 7.0; 95% CI 1.7 to 28.2) and progestogens (OR 4.05, 95% CI 1.6 to10.2). Danazol was shown to significantly lower the duration of menses when compared with NSAIDs (WMD -1.0; 95% CI -1.8 to -0.3) and a progesterone releasing IUD (WMD -6.0; 95% CI -7.3 to -4.8). There were no randomised trials comparing Danazol with tranexamic acid or the levonorgestrel-releasing intrauterine system.