Ovulation induction with clomiphene citrate or letrozole following laparoscopy in infertile women with minimal to mild endometriosis: a prospective randomised controlled trial.

We conducted a prospective randomised controlled trial to explore the efficacy of clomiphene citrate (CC) and Letrozole (LTZ) for improving fecundity in infertile women with minimal to mild endometriosis after operative laparoscopy. We found that the ovulation rate of LTZ (88.7%) and CC (84.5%) were significantly higher than that of Control (70.5%) (p < .001). However, there was no significant difference in cumulative clinical pregnancy rates at 3, 6, 12 months after laparoscopy among the three groups (LTZ: 30%, 34.3%, 38.6% vs CC: 28.6%, 42.9%, 50.0% vs Control: 18.6%, 24.3%, 31.4%, respectively). No significant difference was observed in live-birth rate among the three groups (p = 1.125). For infertile women with minimal to mild endometriosis, ovulation induction with letrozole or clomiphene citrate after laparoscopy significantly increases ovulation rate, which are comparable between them; but does not demonstrate a significant advantage on improving pregnancy rate and live-birth rate when compared to laparoscopy alone.Impact statementWhat is already known on this subject? Endometriosis significantly decreases fecundity of women. Operative laparoscopy was recommended as an effective option to increase spontaneous pregnancy rate in infertile women with minimal to mild endometriosis. However, there is still no optimum treatment strategy for improving fertility of women with endometriosis.What do the results of this study add? For infertile women with minimal to mild endometriosis, ovulation induction with letrozole or clomiphene citrate after laparoscopy significantly increases ovulation rate, which are comparable between them; but does not demonstrate a significant advantage on improving pregnancy rate and live-birth rate when compared to laparoscopy alone.What are the implications of these findings for clinical practice and/or further research? Our results suggest that operative laparoscopy in conjunction with ovulation induction may improve fertility of women with minimal to mild endometriosis. Further research could focus on prolonging cycles of ovulation induction or choosing alternative ovarian stimulation protocols. More RCTs are still needed to compare the efficacy of letrozole with CC in ovulation induction.