Chinese herbal medicine could offer an alternative to standard hormonal treatments for the painful pelvic disorder endometriosis, preliminary research suggests.

In a review of two small clinical trials, researchers found that a particular mix of traditional Chinese herbs worked as well or even better than two conventional hormonal therapies for endometriosis. And it came with fewer side effects.

Both trials, which included a total of 158 women, had shortcomings, however, so it is too early to draw conclusions about the effectiveness of the herbal therapies, the researchers report in a review for the Cochrane Library, a publication of the international research organization the Cochrane Collaboration.

“I think the positive message is that Chinese herbal medicine may offer equivalent benefits to conventional medicine but with fewer side effects,” lead researcher Andrew Flower, of the University of Southampton in the UK, told Reuters Health.

“This may mean that Chinese herbal medicine is more suitable for long-term use,” he added, “but we need more studies to show this.”

In endometriosis, pieces of the tissue that normally lines the uterus (the endometrium) also grow outside the organ - often on the ovaries, the fallopian tubes or elsewhere in the pelvis. Like the endometrium, this misplaced tissue changes with each menstrual cycle, thickening and then breaking down and bleeding.

This leads to a build up of scar tissue outside the uterus, with symptoms including pelvic pain, heavy, painful menstrual periods and fertility problems.

Among the treatments are various drugs that alter women’s hormone levels to prevent new scar tissue and relieve pain. However, they can come with side effects - including acne, unwanted hair growth and menopause-like symptoms like hot flashes.

In one of the trials Flower’s team reviewed, Chinese researchers randomly assigned women to take either an herbal mixture known as Nei Yi Wan or a hormonal therapy called gestrinone after undergoing surgery to remove abnormal tissue growths. The herbal therapy was given both orally and by enema.

After three months of treatment, women in the herb and gestrinone groups showed similar improvements in their symptoms and their chances of becoming pregnant over the next two years.

But while the herbal remedy showed no significant side effects, gestrinone caused acne in 13 of the 49 women treated, and infrequent menstrual periods in 31 women.

The second trial compared the same herbal mix with danazol, a drug that blocks estrogen secretion. After three months, women in both groups reported symptom improvements, but those who took the herb orally and by enema showed greater improvements in painful periods, and a greater reduction in abnormal tissue growths.

The herbs used in both trials are considered in Chinese medicine to be “blood moving,” Flower explained. He noted that research has suggested that the herbs may help regulate pelvic blood flow, as well as modulate immune system activity and inflammation.

SOURCE: Cochrane Library, online July 8, 2009.