In HMG-HCG therapy, the FSH level in serum increases gradually by administering HMG every day. Such an unphysiological phenomenon develops and matures many follicles simultaneously, leading to OHSS and multiple pregnancy. Contrarily in the every-other-day administration, the FSH level in serum remains almost unchanged or increases only slightly and less mature follicles are developed. The risk of causing OHSS and multiple pregnancy is lowered in this way. The every-other-day administration is therfore considered to be a valuable method causing less side effects. The demerit of lower ovulation rate in the every-other-day administration could be amended by some methodological improvement. It is concluded that this a promising therapy
