Ovarian Hyperstimulation Syndrome Due to Exogenous Human Chorionic Gonadotropin (hCG) Presenting More Than 7 Days After hCG Administration

We present a case of ovarian hyperstimulation syndrome (OHSS) occurring 8 days after human chorionic gonadotropin (hCG) administration. OHSS is classified as late type if it occurs 12 to 17 days after hCG administration and early type if it occurs within 7 days. Thus, the condition in this patient did not fit the definition of early or late OHSS. The OHSS was mild, and she recovered in approximately 10 days without requiring admission. The patient was not pregnant, and the OHSS was shown to be induced by exogenous hCG administration not endogenous hCG. In conclusion, OHSS can occur 8 to 11 days after hCG administration and it is important to distinguish whether OHSS is induced by endogenous or exogenous hCG.