At least half of reproductive-age women cope with regular menstrual cramps -- one of the main reasons why young women miss work and school.
But now, a small trial may have zeroed in on a natural remedy that could provide some relief: high doses of vitamin D.
"Vitamin D appears promising for the treatment of inflammation-related pain syndromes and one of them is menstrual cramping pain," said Dr. JoAnn Manson, chief of the Division of Preventive Medicine at the Harvard-affiliated Brigham and Women's Hospital, who co-authored a commentary on the new trial, also published in the Archives of Internal Medicine.
In the new Italy-based study -- the first to look at the impact of a single, high-dose of vitamin D on menstrual cramps -- researchers enrolled 40 women between the ages of 18 and 40. Half of the women received a single, high dose of vitamin D five days prior to the expected start of their next period; the other half got a placebo.
After two months, the women in the vitamin D group reported that their pain scores decreased by 41 percent, on average. Women with the most severe pain at the study's start experienced the greatest reduction during the trial.
Manson explained that it is possible that high doses of vitamin D may help decrease pain by modulating the pathways of prostaglandins, chemicals involved in inflammation and pain which trigger uterine muscle contractions. In general, higher levels of those hormone-like substances means more pain.
But experts caution that the dose of vitamin D used in the study -- 300,000 international units -- is extremely high. The Institute of Medicine's recommended dietary allowance of vitamin D is 600 IU per day; its upper-level intake recommendation is 4,000 IU per day.
Recent studies have highlighted the potential risks associated with such high intake levels. A study in the Journal of the American Medical Association found a possible link between administering a high-dose of vitamin D, and an increased risk of fractures and falls in older women, while a recent paper in the American Journal of Cardiology suggested that while vitamin D can help with cardiovascular inflammation, too much may do more harm than good.
"This is a very large dose. It's not something that most people in the OB-GYN community would be comfortable using, so if people are going to their OBs to ask for this, it probably would not be given," said Dr. Kathy Hoeger, a professor in the Department of Obstetrics and Gynecology at the University of Rochester.
Hoeger said that the first line of therapy for most women are non-steroidal, anti-inflammatory drugs, like ibuprofen or naproxen (Aleve) -- both over-the-counter and prescription strength, if that is not effective. Hormonal birth control may also be prescribed to help reduce the severity of women's menstrual cramps.
Manson said that women seeking a more natural remedy for menstrual pain may want to talk to their doctors about taking a vitamin D supplement to see if it confers any positive effects.
"This research is really in its infancy, but if someone is having pain like this, they may want to give vitamin D a try," she said, explaining that it can be difficult to get more than 400 to 600 IU per day of vitamin D from dietary sources like fish, eggs and fortified milk. Moderate sun exposure also contributes to the production of vitamin D.