This is a nice case of class III Müllerian duct anomaly: uterus didelphys, also, with happy end of pregnancy with cesarean section and birth a healthy child. 

Müllerian duct anomalies (MDAs) are congenital anatomic abnormalities of the female genital tract that arise from nondevelopment or nonfusion of the müllerian ducts or failed resorption of the uterine septum, with a reported incidence of 0.5%–5.0%. MDAs are clinically important because they are associated with an increased incidence of impaired fertility, menstrual disorders, and obstetric complications. MDAs are also associated with an increased incidence of endometriosis and obstructed uterine drainage, which may occur in patients with unicornuate uterus or uterus didelphys (which is reported to occur in 0.1–0.5% of women).