Clomiphene citrate versus letrozole: molecular analysis of the endometrium in women with polycystic ovary syndrome.

Author(s): Wallace KL, Johnson V, Sopelak V, Hines R

Affiliation(s): Department of Obstetrics & Gynecology, University of Mississippi Medical Center, Jackson, Mississippi 39216, USA. kwallace2@umc.edu

Publication date & source: 2011-10, Fertil Steril., 96(4):1051-6.

OBJECTIVE: To compare the effect of clomiphene citrate (CC) and letrozole on endometrial receptivity in women with polycystic ovary syndrome (PCOS). DESIGN: A randomized controlled trial. SETTING: University teaching hospital. PATIENT(S): Ten anovulatory women with PCOS and 5 fertile ovulatory women. INTERVENTION(S): Patients received 2.5 mg of letrozole on cycle days 3-7 (5 patients, 1 cycle) or 50 mg of CC on cycle days 5-9 (5 patients, 1 cycle). MAIN OUTCOME MEASURE(S): Serum estrogen (E) and progesterone (P) endometrial protein and messenger RNA (mRNA) expression of leukemia inhibitory factor (LIF), dickkhopf homolog 1 (DKK-1), fibroblast growth factor 22 (FGF-22), and endometrial mRNA expression of LIF/GP130 receptor (LIFR). RESULT(S): No statistically significant differences were observed between groups compared with fertile ovulatory women when serum E and P were examined, or between body mass index (BMI), and cycle day at time of biopsy. Letrozole increased mRNA expression of LIF, DKK1, LIFR, and FGF-22, whereas CC only increased endometrial mRNA expression of LIF. Letrozole mRNA expression directly translated into increased protein expression of like genes in the endometrium. The CC protein expression of DKK-1 was significantly decreased compared with controls. CONCLUSION(S): Letrozole positively influences a number of markers of endometrial receptivity compared with CC. Copyright (c) 2011 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.