Endometrial effects of letrozole and clomiphene citrate in women with polycystic ovary syndrome using spiral artery Doppler

Abstract

Objectives: To compare the effects of letrozole and clomiphene citrate (CC) on endometrial response in PCOS using subendometrial spiral artery Doppler.

Methods: Fifty consecutive patients of anovulatory PCOS were recruited. Twenty-five patients (58 cycles) received 2.5-5 mg of letrozole; 25 patients (56 cycles) received 50-100 mg of CC (both orally on days 5-9 of menses).

Main outcome measures: number of dominant follicles, endometrial thickness (ET), spiral artery resistance index (RI) and pulsatility index (PI) and pregnancy rate.

Results: The mean number of dominant follicles in letrozole group and CC groups was 1.63+/-1.02 and 1.62+/-0.96, respectively (P>0.05). The mean mid cycle ET was 6.9+/-0.74 mm in letrozole group and 5.9+/-0.53 mm in CC group (P<0.05). In letrozole and CC groups, the mean RI of spiral artery were 0.63+/-0.05 and 0.79+/-0.09, respectively, and the mean PI of spiral artery were 1.19+/-0.06 and 1.55+/-0.13, respectively. Both RI and PI in the letrozole group showed significant lower impedance compared to CC group (P<0.05). Pregnancy rate per cycle was 19% (11/58) in the letrozole group and 12.5% (7/56) in the CC group (P>0.05).

Conclusion: The effect of letrozole showed a significantly better endometrial response compared to CC.