I-31: Antihistamine & Ovarian Hyperstimulation syndrome

Background: Ovarian hyperstimulation syndrome (OHSS) is a rare iatrogenic complication of ovulation stimulation. The pathogenesis of OHSS is uncertain. The crucial event appears to be an increase in capillary permeability by vasoactive mediators such as cytokine and histamine. The aim of this study is to evaluate the role of loratadine (antihistamine) in preventing ovarian hyperstimulation syndrome. Materials and Methods: A total of 226 patients, with a history of severe OHSS undergoing IVF-ICSI cycles were randomly selected to receive loratadine (n=110) or placebo (n=116) daily. This study was conducted at Royan Institute. Patients of each group were subdivided to PCO and normo-ovulatory group. Loratadine (10 mg/ daily) was started from beginning of HMG to 3 days after embryo transfer. The main outcome measures were number of retrieved oocytes, serum E2 level of HCG injection day, cancellation rate, number of transferred embryos, occurrence of OHSS and pregnancy rate. Results: Overall, loratadine caused a nonsignificant decreasing in occurance of OHSS in treated patients (p=0.29). The proportion of treated women who had pregnancy was higher than the corresponding proportion of untreated women but the difference was not significant (p=0.27). In other measures there was no significant difference. Conclusion: The addition of loratadine (10mg/ daily) to the standard long protocol for oocyte retrieval increased pregnancy rates and decreased the occurrence of OHSS but in both of them it was not significant.