Improved oocyte quality is obtained with follicle stimulating hormone alone than with follicle stimulating hormone/human menopausal gonadotrophin combination

The aim of this study was to compare the efficacy of pure folliclestimulating hormone (FSH) with that of FSH/human menopausal gonadotrophin(HMG) combination in downregulated cycles. A total of 357 patients wasevaluated retrospectively. Sixty percent of patients in the FSH group and55% in the FSH/HMG group were new; the others were repeat patients.Ovulation was suppressed with leuprolide acetate in all patients, followedby either FSH (n = 218) or FSH/HMG (n = 119). There was no difference inpatients' age, infertility factors, number of ampoules used, length ofstimulation, oestradiol levels on day of human chorionic gonadotrophin(HCG) administration, number of oocytes recovered or the number of embryostransferred. Also, nuclear maturity at aspiration and fertilization rateswere not different between the two groups. FSH stimulation resulted in asignificantly higher percentage of mature oocytes that showed the typical'mature' morphological characteristics (P < 0.0001). The clinicalpregnancy rates per transfer were 40 and 28% in patients stimulated withpure FSH and FSH/HMG respectively (P < 0.05). The significantly highernumber of immature oocytes matured in vitro in the FSH/HMG group (P =0.001) suggests a possible effect on in-vitro maturation, due toluteinizing hormone present in HMG. The difference in mature oocyte qualitymay be an important determinant in the higher pregnancy rates for the FSH-stimulated patients.