The spontaneous LH surge in ovarian hyperstimulation for assisted reproductive technology.

Thirty-seven patients who underwent assisted reproductive technology programme, in vitro fertilisation or embryo transfer and gamete intra-fallopian transfer, were randomised into two groups in order to evaluate frequency of premature spontaneous LH surge when stimulated with different type of hMG. An hMG (FSH:LH = 1:1) was administered for eighteen patients (group A) and the different highly purified hMG (FSH:LH = 19:1) was administered for nineteen patients (group B). Blood samples are drawn from day 3 of the cycle until hCG administration, and serum LH level are measured in the frozen samples. There were no statistical difference in the total amount of hMG used before hCG injection, days of hMG injection and the number of oocytes retrieved between two groups. The premature spontaneous LH surge occurred only one patient in group A (5.6%), but more frequent LH surge was observed in group B (42.1%) (p < 0.05). It is suggested that the different FSH/LH ratio may be the reason for the difference of the incidence of premature spontaneous LH surge.