A Cochrane review included 5 trials with a total of 1 920 women. Two placebo-controlled trials of women with severe form of premenstrual syndrome (PMS) showed less severe symptoms after 3 months with drospirenone (plus ethinyl estradiol 20μg) than with the placebo (WMD -7.92; 95% CI -11.91 to -4.67). The drospirenone group had greater decreases in impairment of productivity (WMD -0.31; 95% CI -0.55 to -0.08), social activities (WMD --0.29; 95% CI -0.54 to -0.04), and relationships (WMD -0.30; 95% CI -0.54 to -0.06). Side effects more common with oral contraceptive (COC) use were nausea, intermenstrual bleeding, and breast pain. Little effect was found on less severe symptoms when comparing drospirenone plus more estrogen to another COC. A two-year trial found the groups to be similar.
Comment: The quality of evidence is downgraded by study quality (high losses to follow-up and several other limitations), by inconsistency (heterogeneity and marked placebo effect), by indirectness (short follow-up), by imprecise results (limited study size), and by potential publication bias (4/5 studies were sponsored by manufacturer).