Congenital vaginal obstruction in a newborn.

A transverse vaginal septum is a horizontal wall of tissue that has formed during embryologic development and essentially creates a blockage of the vagina. It can occur at different levels of the vagina. We report a neonate who was diagnosed antenatally with an enlarged lower abdominal mass suggestive of an enlarged urinary bladder with hydronephrosis and hydroureter. Shortly after birth, she developed urinary retention and neonatal sepsis. Following multiple postnatal investigations, she was found to have a vaginal septum with hydrometrocolpos.