• Pregnancy rate [ Time Frame: one year ]
  

• Ovulation rate Abortion rate Live-birth rate Adverse events [ Time Frame: one year ]
  

Infertile PCOS patients who ovulated under CC or metformin without pregnancy achievement will be enrolled and treated with three trials of COS plus IUI. All patients will be randomly allocated into two different groups (groups A and B). In group A, COS will be obtained using the same ovulatory agent (CC or metformin) employed in the previous ovulatory cycles, whereas in group B using gonadotropins in a low-dose step-up regimen.

All patients eligible will undergo baseline assessment consisting of anthropometric, hormonal, and ultrasonographic evaluations. During the study, the clinical and reproductive outcomes, and the adverse experience will be evaluated and the will be analyzed also categorizing the patients according to ovulatory agent used for COS (CC or metformin).

Data will be analyzed using the intention-to-treat principle and a P value of 0.05 or less will be considered significant. Continuous variables will be analyzed with the unpaired t test and general linear model for repeated measures analysis with Bonferroni test for the post-hoc analysis as required. For categorical variables, the Pearson chi-square and Fisher’s exact tests will be used. Cumulative pregnancy rate, our primary end-point, will be calculated by the Kaplan-Maier method, and the differences between the two groups will be assessed with the log-rank test. Cox proportional-hazards model will be used to calculate the hazard ratio for new pregnancy in both groups.