Three sisters with septate uteri: another reference to bidirectional theory.

A case report of three sisters with different degrees of septate uteri, a rare familial aggregation, is presented. The youngest sister was diagnosed with a complete uterine septum with cervical duplication and complete longitudinal vaginal septum. She also had a bilateral partial ureteral duplication. Investigation of the family showed that the eldest sister had a complete uterine septum and her pregnancy had terminated with a vaginal delivery following premature rupture of the membranes. The asymptomatic middle sister showed an incomplete uterine septum. Finally, the mother was normal with respect to urogenital anatomy. These types of Müllerian anomalies cannot be explained by the classical theory of unidirectional Müllerian duct development; the alternative bidirectional theory is proposed instead. Additionally, the results are suggestive that the prevalence of major uterine malformations may be higher than generally thought, due to asymptomatic cases.