Randomised trial, 1988
Does doxycycline (an antibiotic) help premenstrual syndrome?
Yes, doxycycline significantly reduced PMS symptoms and the improvement lasted 6 months. The researchers found bacteria in the endometrial tissue of most women, suggesting some PMS cases may be caused by infection.
What they did
30 women were randomly assigned to doxycycline or placebo. After treatment, the placebo group also received doxycycline. Women had tissue samples taken from the endometrium (uterine lining) and blood hormone tests. Follow-up continued for 6 months.
What they found
Women taking doxycycline showed a highly significant reduction of symptoms. Women in the placebo group who then received doxycycline also improved. At 6-month follow-up, the symptom improvement was permanent. Endometrial biopsies showed high incidence of out-of-phase endometrium and an unexpectedly high percentage yielded positive findings for mycoplasma, Chlamydia trachomatis, and anaerobic bacteria.
What it means for you
Doxycycline may help PMS, possibly by treating a hidden infection. However, this is only one small study with 30 women, and the finding has not been widely confirmed.
30
women studied
6 months
follow-up duration
3
types of bacteria found
About the study
- Original title
- Effect of doxycycline on pre-menstrual syndrome: a double-blind randomized clinical trial
- Authors
- Toth A, Lesser ML, Naus G et al.
- Journal
- The Journal of international medical research
- Year
- 1988
- Study design
- Randomised trial
- What was tested
- Doxycycline antibiotic versus placebo
- Read the paper
- doi.org/10.1177/030006058801600404