Timing of hCG administration in cycles stimulated forin vitrofertilization

Abstract

The timing of ovulation induction is usually decided according to estradiol plasma concentrations and follicle size. We administered human chorionic gonadotropin (hCG) when at least three follicles of 16 mm or more in diameter and adequate estradiol plasma concentrations were detected. We studied the percentage of mature oocyte-cumulus-corona radiata complexes, estradiol and progesterone concentrations in a heterogeneous sized follicle population (range 10-20 mm, n = 90) to perform a retrospective analysis of the adequacy of criteria adopted for the timing of ovulation induction. Plasma and follicular fluid were obtained from 20 normo-ovulating women (aged 28-37 years) treated with gonadotropin releasing hormone analogs (GnRH-a) and human menopausal gonadotropin (hMG) for in vitro fertilization (IVF). No correlation was found between the mean individual follicular fluid estradiol concentration (500-5640 nmol/l) and the respective maximum concentration in plasma (2-16 nmol/l). The estradiol concentration was similar in all follicles. Total follicular fluid estradiol concentration was found to be correlated with follicular fluid volume (r = 0.771, p < 0.01). On the day of hCG administration, the concentration of estradiol in the plasma but not the follicular fluid was correlated with the number of oocyte-cumulus-corona radiata complexes collected (p < 0.01) and the number of mature complexes (p < 0.01). At oocyte pick-up, the plasma concentration of progesterone was correlated (p < 0.01) with number of complexes collected and the number of mature complexes. The percentage of mature complexes collected (77.5%) was higher than suggested by the number of leading follicles. This indicates that our criteria for administering hCG were adequate and that heterogeneous follicle size does not exclude a high rate of mature oocyte-cumulus-corona radiata complexes.

Delaying the oocyte maturation trigger by one day leads to a higher metaphase II oocyte yield in IVF/ICSI: a randomised controlled trial

“…This can be explained by the different stimulation protocols that have been used and the variations in study designs. The leading follicles have had to reach diameters of 16 to 20 mm in most cases [1,2,21-28]. …”

“…Historically, the moment for triggering oocyte maturation has been based on follicle diameters that were measured using ultrasound and levels of serum estradiol [1,2]. A Cochrane review [3] stated that the use of sonographic criteria alone might be sufficient but that the simultaneous determination of serum estradiol is still recommended as long as large randomised controlled trials have not shown that the incidence of ovarian hyperstimulation syndrome is equal in both groups.…”

A critical review of bi-dimensional and three-dimensional ultrasound techniques to monitor follicle growth: do they help improving IVF outcome?

“…Other authors [ 22 , 23 ] confirmed that follicles below 14 mm diameter seldom contain MII oocytes, both in normal and polycystic (PCO) ovaries. Overall there is evidence that follicles having a mean diameter between 16 and 22 mm are those with the highest likelihood of containing MII oocytes, but even small follicles can occasionally generate MII oocytes [ 24 ].…”

Follicle Measurements Using Sonography-Based Automated Volume Count Accurately Predict the Yield of Mature Oocytes in In Vitro Fertilization/Intracytoplasmic Sperm Injection Cycles

“…In the majority of studies, the cutoff for the leading follicle diameter was 16-20 mm [5,17,22,23,24,25,26,27,28,29]. …”

“…Typically, 5,000-10,000 IU of human chorionic gonadotropin (hCG) was injected when a minimum of three follicles had reached a mean diameter of 16 mm [5]. The level of estradiol in the peripheral blood, a reflection of the estradiol released by the granulosa cells in the growing follicles, was also used to determine optimal timing [6].…”