NEW YORK, Mar 14 (Reuters Health) - For reasons that researchers do not understand, the menstrual cycle seems to affect the severity of irritable bowel syndrome, according to a report.

In the study, investigators in the UK confirmed that symptoms of the gastrointestinal disorder get worse when women are having their period. And in contrast to women who do not have irritable bowel syndrome, or IBS, women with the condition have greater rectal sensitivity during their menstrual period, the researchers note.

IBS, which affects women more often than men, is characterized by abdominal pain, constipation, bloating and diarrhea. Stress, anxiety and depression can exacerbate IBS episodes. Increasing physical activity and adjusting the diet may relieve symptoms, the report indicates.

Sex hormones such as estrogen may be involved in IBS. For instance, abdominal bloating tends to be less common in premenopausal women than in postmenopausal women. And bloating is less frequent in women taking hormone replacement therapy after menopause.

One way to study the function of the gastrointestinal tract is to measure the sensitivity of the rectum. To do this, researchers insert a balloon-tipped catheter into the rectum and inflate it.

Dr. Lesley A. Houghton and colleagues from the University Hospital of South Manchester in Manchester, UK, had previously shown that the menstrual cycle has no effect on rectal sensitivity in healthy women. To gauge the effect of the menstrual cycle on IBS, the researchers measured rectal sensitivity in 29 women with the condition. During the study, the women, who were aged 21 to 44, kept track of their IBS symptoms for a complete menstrual cycle.

Women with IBS tended to experience worse abdominal pain and bloating when they were having their period. The women also tended to have more frequent bowel movements during menstruation. Women with IBS reported having a lower overall sense of well-being during their period, although they were not more depressed or anxious.

In contrast to previous results in healthy women, however, rectal sensitivity in women with IBS was greater during menstruation than during other phases of the cycle, the authors report in the April issue of the journal Gut.

The results suggest that unlike healthy women, "women who have IBS do show variations in rectal sensitivity with the menstrual cycle," Houghton told Reuters Health. The findings suggest that sex hormones may play a role in IBS, she said.

"Why this is the case and why rectal sensitivity increases at the time of menses we do not know," Houghton said.

　　From Reutershealth.com