Aim of the study
This prospective, observational study was undertaken to determine the increase in serum progesterone levels after human chorionic gonadotrophin (hCG) trigger in stimulated IVF/ICSI cycles.
Materials and methods This proof-of-concept study included 11 patients requiring ovarian stimulation for IVF/ICSI and who planned to avail of pre-implantation genetic screening with embryo vitrification of their biopsied embryos at blastocyst
stage. For each study participant, five additional blood samples were drawn at the following specific times in the stimulation cycle, on the morning (10.00–12.00) of the assigned day to induce final oocyte maturation with hCG trigger, immediately
prior to administration of hCG for final oocyte maturation, 1 h, 2 h, and 36 h post hCG trigger. A prediction model, the Gompertz curve, was used to determine serum progesterone levels at intervals between the 2 h post hCG trigger sample and
the day of oocyte retrieval.
Results Statistically significant increases in serum progesterone levels were identified following hCG administration as early as 1 h following trigger (P4 0.57 ng/ml, p < 0.05), 2 h following trigger (P4 0.88 ng/ml, p < 0.001) and on the day of
oocyte retrieval (P4 9.68 ng/ml, p < 0.001). According to our prediction model, the Gompertz curve, the projected serum progesterone level at 4 h post trigger would have achieved a level of 1.45 ng/ml, 8 h post trigger of 3.04 ng/ml, and 12 h
post trigger of 4.8 ng/ml. The very early and significant increases in serum progesterone following hCG trigger are clearly demonstrated in this study.
Conclusion The endometrium is undoubtedly exposed to rapidly increasing serum progesterone levels post hCG trigger that would not be identified until much later in natural menstrual cycles.