Left-sided diaphragmatic hernia (CDH) as well as ductus venosus agenesis (ADV) are rare complex congenital malformations. We present a case of coincidence of these malformations and an abnormally high lung-head-ratio (LHR). The left-sided liver-up CDH and the ADV were diagnosed in prenatal ultrasound examination. In CDH cases lung volume is decreased due to the herniation of abdominal organs into the thorax. With 1.4 the LHR of our patient exceeded the normal ratio in liver-up CDH cases considerably. One explanation for this unusually high LHR might be an altered blood flow due to the coinciding ADV. In ADV cases less blood bypasses the lung through the foramen ovale. Consecutively pulmonary circulation is improved which may constitute as an advantage in CDH cases. Diagnosis, prognostic factors, physiology, and therapy strategy are discussed.