PRL and polycystic ovary syndrome: When stratified by continent, the results indicated that PCOS patients of Asia and Europe did not have significantly different PRL levels than controls (WMD = −0.04, 95% CI: −0.79–0.89, p = 0.911, and WMD = 2.50, 95% CI: −0.64–5.65, P = 0.119, respectively).