Study of the pharmacokinetics of human chorionic gonadotropin and its relation to ovulation

Abstract

The pharmacokinetics of human chorionic gonadotropin (hCG) was studied in 15 normal volunteers and 15 patients undergoing in vitro fertilization (IVF). Each subject received 6000 IU hCG, intramuscularly (im), at midcycle, and serum was assayed for hCG frequently for 16 hr. All 30 subjects achieved hCG concentrations greater than or equal to 10 IU/liter within 2 hr and 19 (63%) did so within 1 hr of injection. The time taken to attain concentrations of greater than or equal to 20 and greater than or equal to 40 IU/liter correlated positively with the subjects' weight and/or surface area, but the correlation was not strong. Eleven of the 15 IVF patients had oocytes retrieved 34-35 + hr post hCG. Three of the 11 showed evidence of prior "undetected ovulation" at the time of surgery (definite in one, presumed in two). Taking into consideration the pharmacokinetics of hCG and other factors that could lead to undetected ovulation, the authors conclude that (1) hCG is rapidly absorbed in the majority of subjects following im injection, (2) ovulation may occur earlier than 36 hr following hCG in some individuals, and (3) implementation of a shorter (than 35 hr) hCG-to-oocyte retrieval interval would be advised if undetected ovulation is to be avoided.

Optimal Ovulation Trigger–Oocyte Pickup Interval in Progestin-Primed Ovarian Stimulation Protocol: A Retrospective Study Using Propensity Score Matching

“…Some studies reported that better oocyte retrieval time varied in long protocol, such as 35–38 h (5), >36 h (4), 35–36 h (27), and 38–41 h (28). As far as natural cycle or mild stimulation cycle are concerned, the shorter interval was reported, such as 32–36 h (29) and 35–36 h (30). For the GnRH antagonist protocol, oocyte aspiration should be scheduled between 36 and 37 h without compromising results (27).…”

Novel Concepts for Inducing Final Oocyte Maturation in In Vitro Fertilization Treatment

“…In 66% of cases, the largest follicle was the first to rupture and the mean time to ovulation following hCG was 38.3 hours, although the range was between 34 and 46 hours ( 183 ). In 1990, Nader and Berkowitz ( 184 ) found that ovulation occurred within 36 hours following intramuscular hCG administration in some women, and thus suggested that an interval <35 hours between hCG administration and oocyte retrieval be used. This was in keeping with evidence from clomiphene-stimulated cycles that suggested that the interval between hCG administration and ovulation was <34 hours for most patients, but could extend to >39 hours in some patients ( 185 ).…”

The time interval between hCG priming and oocyte retrieval in ART program: a meta-analysis

“…Physiologic studies suggest that ovulation occurs anytime from 24 to 56 h after the onset of LH surge, with a mean time of 32 h [7]. Nader et al [8] studied the pharmacokinetics of hCG and its relation to ovulation and concluded that ovulation may occur earlier than 36 h in some women, they advised aiming for a <35 h interval if ovulation is to be avoided. In most in vitro fertilization (IVF) programs, the commonly practiced interval was 32 to 36 h that was derived from the studies on patients who used Clomiphene Citrate (CC) and/or human menopausal gonadotropin (hMG) for ovulation induction [9][10][11].…”