Incidence of severe ovarian hyperstimulation syndrome with extremely elevated serum estrogen levels

The incidence of ovarian hyperstimulation syndrome (OHSS) is directly correlated with the pre-human chorionic gonadotropin blood estrogen (E) levels. The higher the E content, the greater the chances of OHSS. However, even when the E levels are very high, only 2.96% of the patients developed severe OHSS. Younger women with primary ovarian dysfunction are more at risk than older women. Human chorionic gonadotropin should be withheld when the estradiol levels are over 4,000 pg/ml; however, the patients should be individualized, since some patients--particularly older women--may require higher blood estradiol levels for successful ovulation induction.