Modern management of ovarian hyperstimulation syndrome

The number of women receiving ovulation induction has markedly increased with the advent of medically assisted reproduction. Consequently, ovarian hyperstimulation syndrome (OHSS) has become a frequent clinical problem. It is a potentially life-threatening situation. In its severe forms it is complicated by haemoconcentration, hypovolaemia, hypotension, acute renal insufficiency and thromboembolism. The pathophysiology of OHSS is poorly understood. The occurrence of OHSS correlates well with the level of oestradiol, the number of follicles, and administration of human chorionic gonadotrophin (HCG). The risk is increased in polycystic ovarian disease. The aim of this paper is to review critically the published literature on prediction, prevention and modern management of OHSS. Complete prevention of OHSS is not possible although several methods are used to predict and reduce its occurrence. Endocrine profile and ultrasonic follicular monitoring are the mainstays of prediction. The presence of a large number of small and intermediate size follicles at sonography is a risk factor. Withholding HCG, continuation of gonadotrophin-releasing hormone analogues and cryopreservation of embryos are optional courses of action for prevention. Mild OHSS is usually self-limiting and requires no active therapy. Moderate and severe cases are treated by correction of fluid and electrolyte imbalance, and by prevention of thromboembolism. The use of surgery is limited to cases of torsion or rupture of ovarian cysts, or the presence of concomitant ectopic pregnancy. Aspiration of the ascitic fluid, preferably by the transvaginal route, is recommended in cases with severe ascites.