This paper comprises a systematic review and meta-analysis of the effects of estrogen therapy on symptoms suggestive of overactive bladder (OAB) in post-menopausal women. The researchers identified 11 randomised trials which included a total of 430 participants; 236 individuals received estrogen therapy and 230 were placebo controls. Estrogen therapy included treatment administered systemically or locally as estriol, estradiol, conjugated estrogen, or estradiol and estriol. Overall, the researchers found that estrogen therapies were associated with statistically significant improvements in all outcomes: diurnal frequency, nocturnal frequency, urgency, number of incontinence episodes, first sensation to void, and bladder capacity. Local therapies had statistically significant benefits on all outcomes, whereas systemic therapies only caused significant improvements to incontinence episodes and first sensation to void.