Comparison between the effect of coasting when used with both GNRH antagonist and GNRH agonist protocols in control of serum estradiol in prevention of severe ovarian hyperstimulation syndrome

ABSTRACT

Ovarian hyper stimulation syndrome [OHSS] is an iatrogenic potentially life threatening condition resulting from excessive ovarian stimulation. Coasting has been the most commonly used technique and has become the first choice for prevention of severe OHSS in high risk patients, however, prolonged coasting was found to have adverse prognosis. Combining both the use of a GnRH antagonist protocol, and coasting, and comparing it with coasting in long GnRH agonist protocol in controlling the serum Estradiol [E2] level in patients at risk of developing OHSS. Retrospective randomized study. Private infertility Center. 61 patients were included in the study all with the risk of developing severe OHSS, in which coasting was performed once the serum E2 < 3500 pg/ml, with < 20 follicles, with the leading follicle diameter 16 mm. They were divided into 2 groups according to the stimulation protocol used. Group A [n=33] [Flexible GnRH antagonist HMG-FSH protocol], and Group B [n=28] [Long GnRH agonist HMG-FSH protocol]. Primary outcome measures were the number of stimulation days, E2 level before starting to coast, peak E2 level reached, number of days for E2 to drop to a safe level, number of coasted days, E2 level on day of HCG, and percentage of E2 drop from the peak level. Secondary measures were number of oocytes retrieved, number of high quality embryos, and pregnancy rate, and incidence of severe OHSS in both groups. Coasting is more efficient with the GnRH antagonist protocols, than with the GnRH agonist protocol, without any effect on the pregnancy outcome. This is caused by the better pituitary suppression achieved by the antagonist that ensures E2 drop to safe levels, besides its prevention of premature luteinization that is common in cases of prolonged coasting