| Background and Objective;Polycystic ovary syndrome(PCOS)is one of the most common endocrine diseases affecting fertile reproductive women,and is the major cause of anovulatory infertility,and it is characterized by hyperandrogenism,chronic anovulatory cycles and oligomenorrhea or amenorrhea.Clomiphene citrate(CC)has been widely used in the treatment of infertility since its introduction into clinical practice in the 1960s.But,despite high rates of ovulation,pregnancy rates per cycle remain relatively low.An antiestrogenic effect of CC on the endometrium and cervical mucus has been postulated.Moreover,The patients with inadequate response to CC have been observed in 20%～25%patient on clomiphene.For women who experience this adverse effect of clomiphene,the next step is induction of ovulation with gonadotropins,which significantly increases both the cost of and risk associated with treatment,particularly for women with polycystic ovarian syndrome,who are at increased risk of ovarian hyperstimulation syndrome(OHSS)and multiple pregnancies.Because of these problems,we proposed a new method of ovulation induction that could avoid many of the adverse effects of CC.Letrozole is the above new method.It is a potent reversible aromatase inhibitor that has been used to treat for postmenopausal women with metastatic breast cancer.LE is a typeⅡ,third generation,cytochrome P-450 linked aromatase inhibitor that reversibly suppresses E biosynthesis.When administered in the early fouicular phase,letrozole,by blocking E synthesis reduces the negative feedback effect of E on the hypothalamus or hypophysis.The excellent oral bioavailability and relatively short half-life(45 hours) make letrozole a viable alternative to clomiphene for ovulation induction.The aim of this study was to study the effect of letrozole(LE)on the induction of ovulation in patients with Polycystic Ovary Syndrome(PCOS).Materials and Methods;This trial was performed in Reproduction Medicine Center of Shandong Provincial Hospital and Department of Obstetrics and Gynecology Gaotang Town People' s Hospital of Shandong Province,seventy five patients with PCOS from Februaly 2007 to July 2007 were included.thirty PCOS patients were treated with LE..Their follicle growth,endometrial thickness,cervix mucus score and serum E2 level were observed,and compared with those of 45 PCOS patients treated with clomiphene citrate(CC).The patients with inadequate response to CC of 30 PCOS patients.The statistical analyses were performed using SPSS12.0 for windows statistical package.Measurement data are expressed(?)±S.Independent-Samples t-test was used when compare mean.Enumeration data are expressed as%,x2 test was used.The differences are considered to be statistically significant if P＜0.05Results;1.ovulation occurred in 38 cycles(65.5%)in LE group,The mean endometrial thickness on the day of hCG administration were 0.89cm and mean cervix mucus score were 11.90.both were higher than CC group.38 LE cycles resulted the mean number of 1.077 mature follicles in each cycles,Mean serum E2 level was167.88pg/ml on the day of hCG administration Both were lower than CCgroup.in 30 LE treatment patients,there was no OHSS.2.The 14 PCOS patients with inadequate response to CC in LE group.The average age was 28.64±3.32 yrs,the average duration of infertility was3.93±3.17, the average BMI was24.40±2.96.With letrozole treatment,ovulation occurred in 8/14.The mean endometrial thickness was 0.83±0.11cm,the mean cervix mucus score was 11.33±1.15,the mean serum E2 level was 141.33±34.03pg/ml.Moreover, Pregnancy was achieved in 2 letrozole patients with inadequate reponse to CC.Conclusions;1.Oral administration of the aromatase inhibitor letrozole is effective for ovulation induction in PCOS,the ovulation rate was higher in LE group,LE appears to avoid the unfavorable effects on the endometrium and cervix mucus.2.Letrozole is effective for induction of ovulation in PCOS patients with inadequate reponse to CC. |
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