Contraceptive pills do not lead to major weight gain

Many women and clinicians worry that taking combination hormonal contraceptives will result in weight gain.

This anxiety deters some women from using this highly effective form of contraception. A systematic review of available data could however find no evidence of this effect. The results of this research are published in the latest update of The Cochrane Library.

“Sometimes women stop using these contraceptives because they believe they are causing them to put on weight. But in trials that compared women taking different hormonal contraceptives, a similar number of women in the comparison group also dropped out for the same reason,” says Dr Laureen Lopez, a co-author of the study, who works in the Clinical Research Department of Family Health International, in North Carolina, USA.

The Review Authors examined data from 44 trials that had considered the issue. Only three studies used a placebo; the others compared two types of hormonal contraceptives. The Review Authors believe that further randomised controlled trials are needed to discover the variety of factors that influence a possible weight gain in women taking combination hormonal contraceptives.

That said, the current evidence does not indicate a causal relationship between combination contraceptives and weight gain. The Review Authors suggest that weighing women who use combination contraceptives may not be as helpful as counselling about typical weight gain over time.