Ovarian hyperstimulation syndrome: Aetiology, prevention and management

Ovarian hyperstimulation syndrome is a serious and potentially life-threatening complication of infertility treatment. The symptoms are generally triggered by human chorionic gonadotrophin (hCG) following ovulation induction in an in vitro fertilisation cycle. It is believed that the underlying pathology is a shift of protein-rich fluid from the intravascular space to extravascular compartments. The exact aetiology has not been established however it is felt that vascular permeability plays a key role which may be mediated by the immune system, VEGF and the ovarian rennin–angiotensin system. Prevention of the syndrome is important and involves monitoring of patients undergoing ovulation induction, modifying treatment regimens and pharmacological interventions. The management of patients depends upon the severity of the condition. There should be a low threshold for hospital admission where close monitoring, replacement of intravascular volume, thromboprophylaxis and paracentesis (if required) can be effected.