Study: Women Who Use Birth Control Pill 1.5 Times More Likely to Develop Bowel Disease

LONDON, UK, March 13, 2009 - A study on the role of oral contraceptives in the cause of inflammatory bowel disease, published in the American Journal of Gastroenterology, found that women who use the pill are one and a half times more likely to develop Crohn's disease (CD) or ulcerative colitis (UC) than women who have not used oral contraceptives.

The research by doctors at the Gastroenterology Unit of St. Mary's Hospital, Imperial College, and the Department of Surgery of St. Mark's Hospital, London, reported that a total of 75,815 patients were involved in the study of the etiology of UC and CD between 1983 and 2007. Of these women, 36,797 used the oral contraceptive pill (OCP) and 39,018 did not.

The report stated that the relative risk of developing Crohn's disease increased with a prolonged exposure to the OCP. Whereas the overall average of increased risk was 1 1/2 times, the relative risk of developing CD for a woman who has used the pill for three years increases to almost 3.5 times.

This study has also shown that the risk associated with OCP exposure was reversed to that of the non-exposed population after stopping the use of the drug.

The adjustment of the results for smoking was an important aspect of this analysis, since it was found that smokers are more likely to take the OCP, and oral contraceptive users have been reported as more likely to smoke. The adjustments for smoking increased the relative risk of CD and decreased the risk of UC.

The study also suggested that a reduction in the estrogen and progesterone dosages in OCPs over the last two decades has not reduced the relative risk of inflammatory bowel disease in women who use the contraceptive pill.

An abstract of the study is available here.

Read related SLN articles on the dangers of the oral contraceptive pill:

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