Low-dose hCG as trigger day and 35 hr later have different ovarian hyperstimulation syndrome occurrence in females undergoing In vitro fertilization: An RCT.

Background: Ovarian hyperstimulation syndrome (OHSS) is an iatrogenic complication, which can cause high morbidity and mortality. Use of gonadotropin releasing hormone (GnRH) agonist instead of human chorionic gonadotropin (hCG) in GnRH antagonist cycles causes luteinizing hormone surge by GnRH stimulation which reduces the risk of OHSS by reducing the total amount of gonadotropin; however, there is no possibility of transferring fresh embryos.

Objective: The current study aimed to evaluate the effect of hCG along with GnRH agonist administration in the occurrence of OHSS and pregnancy rate in females undergoing in vitro fertilization.

Materials and Methods: The current randomized clinical trial was conducted on 80 cases in 2 groups. Gonal-F was used to stimulate the oocyte from the second day of menstruation. When follicle size was 12-14 mm, GnRH antagonist was added to the protocol till the detection of more than two follicles greater than 18 mm. Then, GnRH agonist was added to the protocol as a trigger. In group A, 35 hr after the administration of GnRH agonist, the low-dose human hCG, 1500 IU, was used. In group B, low-dose hCG, 1500 IU, was used at the same time by GnRH agonist administration. The rate of pregnancy, OHSS, and its severity were compared between 2 groups within 2 wk.

Results: There was no significant difference regarding chemical and clinical pregnancies between the 2 groups. Severe OHSS was significantly higher in group B (p= 0.03).

Conclusion: Administration of hCG 35 hr after GnRH agonist administration results in lower rate of severe OHSS.