Objective: To evaluate the effect of the aromatase inhibitor letrozole in the prevention of ovarian hyperstimulation
syndrome (OHSS) in patients at risk during controlled ovarian hyperstimul (COH).
Design: This is a prospective, randomized, double-blind study on women at risk of the development of OHSS during COH
using gonadotropin-releasing hormone (GnRH) antagonist protocol
Patients and Methods: This research was conducted at the Center of Assisted Reproduction, Om El-kora Hospital,
Tanta, Egypt. Sixty patients, who were considered at risk of the development of OHSS during COH were enrolled in this
study. Ovarian stimulation was performed using GnRH, whereas cabergoline (0.25 mg) given twice daily or letrozole
(2.5 mg) twice daily from the day of oocyte retrieval for one week.
Results: In the cabergoline group, two cases (6.6%) developed mild OHSS and one case (3.3%) developed moderate
OHSS versus 8 (26.6%) mild OHSS and 6 (20%) moderate OHSS in the letrozole group. On the other hand, there was no
statistically significant difference in the number of cases that developed severe OHSS in both groups where only one case
(3.3%) developed severe OHSS in the cabergoline group vs. two (6.6%) cases in the letrozole group.
Conclusion: Although letrozle administration during the luteal phase of ART cycles can reduce the high E2 level in
hyper-responding patients, but it cannot prevent the development of early OHSS. On the contrary, Cabergoline can
effectively prevent the development of early OHSS.