Congenital uterine abnormalities are structural anomalies present from birth. Examples include a bicornuate uterus (heart-shaped uterus), septate uterus (a partial or complete division of the uterine cavity), and unicornuate uterus (a uterus with one side underdeveloped). These anomalies can affect fertility and pregnancy outcomes. Diagnosis is typically made using imaging techniques like ultrasound or MRI.