Treatment of an antenatally diagnosed fetal ovarian cyst by needle aspiration during the neonatal period.

An ultrasound scan revealed an ovarian cyst in the fetal lower abdomen at 29 weeks of gestation. Repeated examinations demonstrated that the cyst increased in size to 6.5 cm x 6.1 cm x 5.0 cm at 33 weeks of gestation, and the cyst showed no complications between 29 weeks of gestation and early infancy. The female infant was vaginally delivered at 41 weeks of gestation without any complications. Transabdominal needle aspiration of the cyst fluid was performed on the 14th day after birth. The concentrations of estrone, estradiol, estriol, and progesterone in the cyst fluid were almost the same as those in the infant's serum, while the concentration of pregnenolone was six times that in the infant's serum. Cytology of the cyst fluid was negative. The cyst thus seems to have been a non-functioning simple cyst of ovarian origin. Follow-up until the baby was one year old showed no recurrence of the cyst.