A common operation for ulcerative colitis renders nearly 50 percent of female patients infertile, according to a new report. By contrast, when the disease is managed with medications alone, the infertility rate is 15 percent, similar to the rate seen in healthy women.

Ulcerative colitis is a serious disease in which the body’s immune cells attack the inner lining of the large intestine or colon resulting in severe bouts of bloody diarrhea. In the long-term, the disease also increases the risk of colon cancer. While the disease is often successfully treated with medications alone, many patients require surgery, frequently undergoing an operation called colectomy with ileal pouch anal anastomosis (IPAA).

With IPAA, the colon is removed completely and the last portion of the small intestine, the ileum, is attached to the anus. Unlike some other operations used to treat ulcerative colitis, IPAA does not leave the patient with an opening or “ostomy” on the skin where stool exits.

“Radiologic studies have shown that women often have blockage of the fallopian tubes after undergoing IPAA,” senior author Dr. Peter D. Higgins, from the University of Michigan at Ann Arbor, told Reuters Health. “Still, past studies have yielded widely varying rates of infertility, so we’ve been unable to tell patients what their odds (are) of becoming infertile after the procedure.”

According to the new report, which appears in the online issue of the medical journal Gut, IPAA has several advantages over long-term drug therapy as a treatment for ulcerative colitis, including complete elimination of disease flare-ups and colon cancer risk, as well as a much lower cost. Despite these benefits, most patients opt for medical therapy, Higgins said.

A search of published reports, meeting abstracts, and other sources identified 189 studies potentially relevant to investigating the association between IPAA and infertility. Ultimately, eight studies, involving more than 500 patients, met selection criteria.

IPAA more than tripled the risk of infertility compared with medical therapy. Infertility was defined as failure to conceive after 12 months of attempts, the authors note.

Higgins said that there is evidence that other surgeries for ulcerative colitis, such as removing the colon but leaving the rectum intact, may have lower infertility rates. Treatments that reduce scarring at the time of surgery or work to keep the fallopian tubes open may help cut the infertility rate seen with IPAA, he added.

Gut 2006.