A warm patch on the belly eased period pain as well as ibuprofen did
Mothers and friends have always said: put something warm on it. In 2001 Akin and colleagues tested that advice. For two days, 84 women with painful periods wore a patch on the lower belly and took tablets. Some got a patch that held 38.9 °C for 12 hours a day, the rest an identical unheated one. The tablets were either ibuprofen, 400 mg three times a day, or a placebo, and the women didn't know which they had.
On a six-point pain relief scale, the unheated patch with a placebo scored 1.95. The warm patch with a placebo scored 3.27; ibuprofen with an unheated patch, 3.07. Heat on top of ibuprofen didn't relieve more pain than ibuprofen alone, but it worked faster: noticeable relief came after a median of an hour and a half instead of nearly three.
One trial doesn't prove much. In 2018 Jo and Lee, two Korean researchers, searched for every randomised trial of heat for period pain and found only six, mostly small. Three compared heat with painkillers, and heat came out slightly ahead. The authors call this only suggestive evidence, and whether heat keeps helping cycle after cycle hasn't been tested.
The patches and belts in these trials held 39–40 °C for 8 to 12 hours. The hottest was a 50 °C hot-water bag, and that trial saw mild burns and itching. Only three of the six trials reported on side effects, and none were serious. If neither heat nor a pill touches the pain, that's worth taking to a gynaecologist. Mum's advice held up, as long as the heat is warm rather than hot.
Sources
- Akin MD, Weingand KW, Hengehold DA, Goodale MB, Hinkle RT, Smith RP. Continuous low-level topical heat in the treatment of dysmenorrhea. Obstetrics & Gynecology, 2001; 97(3): 343–349. doi:10.1016/s0029-7844(00)01163-7
- Jo J, Lee SH. Heat therapy for primary dysmenorrhea: A systematic review and meta-analysis of its effects on pain relief and quality of life. Scientific Reports, 2018; 8: 16252. doi:10.1038/s41598-018-34303-z