Preterm Ovarian Hyperstimulation
A 3-month-old female infant presented with swelling of the external genitalia. She had been born prematurely, at 27 weeks of gestation, and had stayed 75 days in the neonatal intensive care unit. The patient was well at discharge, but her mother later noted the gradual development of genital swelling. Physical examination revealed swelling of the clitoris and vulva (Panel A) but was otherwise unremarkable. Laboratory studies showed elevated serum levels of estradiol (310 pmol per liter [80 pg per milliliter]; normal range in a female infant, 20 to 40 pmol per liter [5 to 10 pg per milliliter]) and the gonadotropins follicle-stimulating hormone (17.2 mIU per milliliter; normal range, 0.5 to 2.4) and luteinizing hormone (4.7 mIU per milliliter; normal range, 0.01 to 0.21). Ultrasonography of the abdomen revealed two cysts on the right ovary. The patient received a diagnosis of the preterm ovarian hyperstimulation syndrome, which is characterized by prematurity, vulvar swelling, elevated estradiol and gonadotropin levels, and ovarian cysts. The preterm ovarian hyperstimulation syndrome is a self-limiting condition and resolves spontaneously without treatment. Serial measurements of serum levels of gonadotropins and estradiol were performed during follow-up, while the patient was receiving no medication. Four weeks after presentation, the estradiol level peaked at 700 pmol per liter (190 pg per milliliter) and then declined, with estradiol and gonadotropin levels gradually returning to normal. Six weeks after presentation, swelling had reduced considerably (Panel B), with complete resolution by 14 weeks (Panel C). Repeat ultrasonography revealed that the ovarian cysts had disappeared, and the infant remained well at follow-up 12 months after presentation.
