OHSS is a potentially serious and often uncomfortable complication of menotropin therapy. The syndrome may occur days to a few weeks following ovulation (when triggered using hCG) if more than one ovarian follicle has developed.
OHSS is caused by an unknown process that occurs within the ovaries, producing a substance (not yet identified) that allows the water from within the body’s blood to leak out of the blood vessels into the pelvis and abdomen (possibly resulting in abdominal distention, bloating and dehydration). The ovaries become very fragile (easily traumatized) so that any sudden motion or even relatively mild flexion (bending) at the hip (such as typing at a desk) can cause pelvic pain. The patient must drink large amounts (1-2 liters) of a balanced electrolyte solution (Gatoraid, Pedialyte or Poweraid are good) to replace the water that is collected in the pelvis (rehydration). She must also try to limit her activities to avoid ovarian trauma and pain.
In severe cases of OHSS, hospitalization with an intravenous catheter (for fluid replacement) may be required. Rarely, fluid can also collect around the lungs to limit breathing (resulting in shortness of breath), or the dehydration can be so severe that the patient is at risk for renal (kidney) failure (shutdown), abnormal blood clotting and/or pulmonary emboli. The treatment of OHSS is fluid replacement, limited activity (possibly bed rest) and supportive care. Medications to assist kidney function (such as IV dopamine) and/or mechanical removal of some of the abdominal fluid that has collected (with a needle ideally under ultrasound guidance) can be quite helpful.
As a rule, OHSS will not occur if the hCG (Profasi) injection to trigger ovulation is withheld. This results in the slow removal of the follicles that have developed and also prevents (in all but rare cases) ovulation. The risk for severe OHSS is correlated (roughly) to the number and size of the ovarian follicles (on ultrasound) and the serum estradiol concentrations (in the monitored blood work). Therefore, cycle monitoring is absolutely essential during controlled ovarian hyperstimulation with menotropins.