Clinical aspects of ovarian hyperstimulation syndrome

Ovarian hyperstimulation syndrome (OHSS) is characterized by massive transu dation of protein-rich fluid (mainly albumin) from the vascular space into the peritoneal pleural and to a lesser extent to the pericardial cavities. The intensity of the syndrome is related to the degree of the follicular re sponse in the ovaries to the ovulation inducing agents. OHSS is still a thr eat to every patient undergoing ovulation induction. The pathophysiology of OHSS is of extreme importance in the face of the increased use of ovulatio n induction agents as well as the development of sophisticated assisted rep roductive techniques. The correlation found between plasma cytokine activit ies and the severity of OHSS suggests that plasma cytokines may be involved in the pathogenesis of OHSS and may serve as a means of monitoring the syn drome during the acute phase and throughout convalescence. The interactions between cytokine and non-cytokine mediators of the syndrome, such as the r enin-angiotensin system and vascular endothelial growth factor were recentl y clarified. Awareness of possible mechanisms and factors in the pathophysi ology of OHSS will hopefully provide opportunities to design specific treat ment regimens effective for both prevention and treatment of this potential ly fatal iatrogenic condition. Among IVF patients with severe and critical OHSS, pregnancy rates, multiple gestations, miscarriage, preterm premature rupture of the membranes, prematurity, and low birth weight rates are signi ficantly higher than those reported previously for pregnancies after assist ed conception. The incidence of other obstetrical complications, as well as congenital malformations and Cesarean section rates are not significantly different. (C) 1999 Elsevier Science ireland Ltd. All rights reserved.