Summary

Preterm ovarian hyperstimulation syndrome is a rare syndrome in which preterm infant girls have hypogastric, upper leg and labial swelling accompanied by elevated serum oestradiol levels and ovarian follicular cysts on ultrasound. Our case is an infant born at 23 weeks gestational age who at 30 weeks postconceptional age (PCA) developed elevated 17-hydroxyprogesterone on her newborn screen with associated clitoromegaly and a ventral groove on the inferior aspect of the erectile tissue. An initial pelvic ultrasound at 32 weeks PCA demonstrated a normal appearing uterus, but the ovaries were not visualised. At 39 weeks PCA, follicular ovarian cysts were noted bilaterally (31×26×21 mm on left and 38×25×36 mm on right). Without treatment, oestradiol and testosterone levels began normalising by 42 weeks PCA. After this point, the right ovarian cysts had resolved and the left ovarian cyst continued to diminish in size.