Assessment of luteinizing hormone level in the gonadotropin-releasing hormone antagonist protocol.

In the GnRH-antagonist multiple-dose protocol, the LH level retrieved from a single measurement during ovarian stimulation and concomitant GnRH-antagonist administration can vary according to [1] the time point of sampling with respect to the GnRH-antagonist injection and [2] episodic changes in circulating LH concentration due to the pulsatile release of LH from the pituitary gland. To exemplify the size of pharmacodynamic effect of a single 0.25-mg cetrorelix administration on LH concentration profile and pulsatility, we measured endogenous LH levels every 15 minutes from 8 hours before the first cetrorelix administration until 24 hours thereafter on ovarian stimulation day 6 and 7 in a single patient.