[A new criterion for hCG administration in human IVF programs: importance of serum LH levels]

A new, simple criterion for hCG administration to induce ovulation for IVF is described. Serum LH levels were measured daily, and hCG was administered, independent of follicle size or estradiol levels, the night of the day when the LH level first exceeded the J level, defined as the minimum value + (the day 3 value-the minimum value) x 1/3. Based on this hCG criterion, the total and ongoing pregnancy percentages per cycle were 35% and 27%, respectively. It appears that the pregnancy rate decreases when hCG is administered one day before or one day after the criterion is met. Pregnancies resulting from hCG administration based on the criterion had a wide range both of dominant follicle diameter (14-21 mm) and estradiol level (229-2,050 pg/ml). The serum LH level is recommended as a useful parameter in timing hCG administration for IVF.