Combination estrogen-progestin contraceptives and body weight: Systematic review of randomized controlled trials

OBJECTIVE: Many women and clinicians believe that combination estrogen-progestin contraceptive use can lead to weight gain. This concern can deter women from starting hormonal contraception or lead to premature quitting. This review evaluated the association between combination contraceptive use and change in body weight. DATA SOURCES: The computerized databases CENTRAL, MEDLINE, ENMASE, Popline, and LILACS (from their inception to 2002) were used to conduct this review. Known investigators and manufacturers were contacted for information about other trials not discovered in the database search. METHODS OF STUDY SELECTION: All English-language, randomized controlled trials measuring weight change that were at least 3 treatment cycles in duration and that compared a combination contraceptive to a placebo or to a combination contraceptive that differed in drug, dosage, regimen, or study length were eligible for inclusion. Of the 570 reports of randomized controlled trials of eligible interventions that were identified, 42 trials were included in the systematic review. TABULATION, INTEGRATION, AND RESULTS: Two reviewers independently abstracted data from the eligible trials using a standard form. Depending on the data available, the weighted mean difference using a fixed effect model with 95% confidence intervals was calculated for the mean change in weight between baseline and posttreatment measurements or the Peto odds ratio with 95% confidence intervals was calculated by using the proportion of women who gained or lost more than a specified amount of weight. The 3 placebo-controlled, randomized trials did not find evidence supporting a causal association between combination oral contraceptives or a combination skin patch and weight gain. Most comparisons from the 40 trials that compared 2 or more combination contraceptives showed no substantial difference in weight. In addition, discontinnation of combination contraceptives because of weight gain did not differ between groups when this factor was studied. CONCLUSION: Available evidence is insufficient to determine the effect of combination contraceptives on weight, but no large effect is evident. ((C) 2004 by The American College of Obstetricians and Gynecologists.).