Clinical Study On Letrozole Combining With HMG For Induction Of Ovulation

Objective and Background:Polycystic ovary syndrome (PCOS) is one of the most common diseases in gynecological endocrinology, and its incidence is about5%-10%in reproductive-age women and50%～75%in anovulatory infertility. Its clinical manifestation is complex and heterogeneity. Ovulation induction treatment is an ordinary therapy to get pregnancy in this population.Clomiphene citrate (CC) is the first line medicine for ovulation, which is oral non-steroidal selective estrogen receptor modulator (SERM) that improves production of gonadotropins (Gn) through prohibiting negative feedback on the hypothalamus and pituitary to release more Gn, which leads to follicles develop. Its adverse effects cannot be ignored in clinical application, it leads to multiple ovulation, hence increasing the chance of multiple pregnancy, OHSS and CC resistant and so on. The aromatase inhibitors (AIs) have been concerned recent more than10years.Letrozole (LE) is the third generation AIs. As it can prevent the aromatase from generating estrogen, which prohibits negative feedback on hypothalamus and pituitary to increase the production of Gn, which improves follicles to develop. Some studies showed that LE still has effect on the patients who are CC resistant, to induce single follicle to develop, good endometrium thickness and higher PR compare with CC. As so many advantages, LE gets so much attention since it started to be applied in clinical work since2000. This study analyzed the clinical effect of LE with HMG in treatment of PCOS group and none PCOS group, to discuss the effect of LE combined with HMG in clinical reproductive work. And it also investigated factors influencing of the dose of HMG, for facilitating the selection of the most appropriate starting HMG dose for ovarian stimulation.Materials and Methods:This trial was performed in Reproductive Hospital affiliated to Shandong University,97patients from October2010to July2011were included. Among them,64patients were diagnosed with PCOS, and other33patients were none PCOS. ALL of them were treated with LE5mg*5d combined with HMG. Their follicle growth and endometrial thickness were observed and compared between these two groups. The statistical analyses were performed with SPSS16.0for windows statistical package. Measurement data were expressed (X±S). Independent-Samples t-test was used when compare mean. Enumeration data were expressed as%, χ2test was applied. The multivariate and univariate analysis were used to do the correlation analysis. The differences were considered to be statistically significant if P<0.05.Results:In PCOS group,64patients with72cycles participated in the study; the mean endometrial thickness on the day of HCG administration (9.56±2.487)mm, the number of dominant follicle (2.29±2.346), the number of ovulation ovum (1.89±1.648), the incidence with progynova (8.06%),56cycles with follow-up ovulation, among them54cycles with ovulation (96.4%),58cycles with follow-up pregnancy, among them23cycles with pregnancy(39.7%), among them2patients with twins pregnancy and no OHSS;In none PCOS group,33patients with40cycles, the mean endometrial thickness on the day of HCG administration (9.85±1.961)mm, the number of dominant follicle (2.28±2.562), the number of ovulation ovum (1.81±1.424), the incidence with progynova (15%),32cycles with follow-up ovulation, among them30cycles with ovulation (93.8%),31cycles with follow-up pregnancy, among them11cycles with pregnancy(35.5%), among them1patients with twins pregnancy and no OHSS;In this treatment program, the thickness of endometrium, dominant follicle number, ovulation ovum number, the incidence with progynova, ovulation rate and pregnant rate per cycle had no statistical differences in PCOS group and none PCOS group. However, the HMG volume (6.5±2.664) in PCOS group was higher than HMG volume (5.31±1.821) in none PCOS group (P=0.014).Conclusion:LE5mg*5d combining with HMG treatment program has a similar effect in PCOS patient and none PCOS patient, while it costs more HMG in PCOS group. The patients with long menstrual cycle and/or lots of basic follicles need more HMG in this protocol, so the starting of HMG dose should be increased at the beginning to decrease the duration of ovulation and the cost of this process.