Cystic ovaries in a pre-term newborn infant.

Oestrogen-producing ovarian cysts in a very pre-term infant led to swelling of the labia majora and of the lower abdominal wall. Following surgical removal of the left ovary the serum concentration of oestradiol decreased temporarily. Less than 2 weeks after surgery several new cysts appeared in the right ovary. Treatment with medroxyprogesterone acetate resulted in disappearance of these cysts. Simultaneously the serum concentration of oestradiol fell to a normal level.