First author Sunil K. Halder of Meharry Medical College in Nashville -- who conducted the research with Meharry colleagues Chakradhari Sharan and Dr. Ayman Al-Hendy and Kevin G. Osteen of Vanderbilt University Medical Center in Nashville -- said uterine fibroids are the most common non-cancerous tumors in women of childbearing age. Fibroids grow within and around the wall of the uterus.
Thirty percent of women ages 25-44 report fibroid-related symptoms such as lower back pain, heavy vaginal bleeding or painful menstrual periods, the researchers said.
Uterine fibroids also are associated with infertility and such pregnancy complications as miscarriage or preterm labor. Other than surgical removal of the uterus, there are few treatment options for women.
For the study, the researchers examined the genetically predisposed rats to developing fibroid tumors and confirmed the presence of fibroids in 12. The researchers divided the rats into two groups of six each -- those that would receive vitamin D and those that would not.
Half of the rats had small pumps implanted under the skin that delivered a continuous dose of vitamin D for three weeks.
The study, published in the journal Biology of Reproduction, found the fibroids increased in size in the untreated rats but shrunk dramatically in rats receiving vitamin D. On average, uterine fibroids in rats receiving vitamin D were 75 percent smaller than those in the untreated group.