Prevention and management of ovarian hyperstimulation syndrome

Ovarian hyperstimulation syndrome (OHSS) most commonly follows human chorionic gonadotrophin (hCG) administration as part of supraphysiological ovarian stimulation in assisted conception cycles. If risk factors for OHSS are detected pretreatment, stimulation regimes should be modified. Monitoring of ovarian response during gonadotrophin stimulation may identify high-risk cycles, allowing further gonadotrophin to be withheld till the ovarian response settles to safe levels. Complete avoidance of hCG prevents OHSS, but may not be acceptable to patients. Luteal hCG exposure can be minimized by freezing all embryos or by using luteal support with progesterone in preference to hCG. Patients with moderate/severe OHSS should be admitted and receive sympathetic counselling, thrombosis prophylaxis and symptomatic treatment for pain and nausea. Oral rehydration should be encouraged, with intravenous crystalloids for cases with significant nausea. Volume expanders should be used for resistant dehydration and oliguria. Paracentesis may help patients with tense ascites. Complications may require multidisciplinary care.