OBJECTIVETo evaluate the impact of the concentration of circulating luteinizing hormone (LH) in the late-follicle phase on the outcome of in vitro fertilization for normogonadotrophic women.

METHODSIntracytoplasmic sperm injection treatment was conducted in 432 consecutive cycles of normogonadotrophic women. A stimulation protocol with mid-luteal gonadotropin-releasing hormone (GnRH) agonist down-regulation and ovarian stimulation with follicle stimulating hormone (FSH) was used in all cycles. hMG was added when a follicle of > or = 14 mm was present (FSH + hMG group), not in the control group (FSH-alone). LH and oestradiol concentration in the serum on hCG day were detected. Based on LH levels, patients in the FSH + hMG group were again divided into four subgroups: LH < or = 1, 1 < LH < or = 2, 2 < LH < or = 3, and 3 < LH < or = 10 IU/L.

RESULTSOestradiol concentration on the day of hCG injection in the FSH + hMG group was higher than that in the FSH-alone group [(3435.51 +/- 2029.01) pg/ml vs (2620.62 +/- 1604.80) pg/ml, P < 0.05]. More embryos were transferred in the FSH-alone group than in the FSH + hMG group [(2.77 +/- 0.45) vs (2.22 +/- 0.46), P <0.001]. Fertilization rate, implantation rate, and clinical pregnancy rate were similar between the FSH-alone group and the FSH + hMG group (77.52% vs 78.31%, 41.42% vs 41.68%, 64.56% vs 62.64%, P > 0.05), as well as among the four subgroups of the FSH + hMG group (P > 0.05).

CONCLUSIONThe adding of suitable amount of hMG and physiologically limited LH concentration in the late-follicle phase have no negative effect on the outcome of in vitro fertilization/intracytoplasmic sperm injection for normogonadotrophic women.