During the 5 last years, 6 French PICU from GFRUP faced with 12 neonates presenting with early ductal closure after matemal treatment with indomethacin(10 mothers). Pregnancy: The indications for indomethacin were: preterm labour after failure of conventional tocolysis (3 cases; GA: 29 weeks, duration 2 to 18 d, mean total amount 2616 mg); treatment of ill-tolerated polyhydramnios (6 cases; 3 twin pregnancies: GA 30 weeks, duration 4 to 48 d, mean total amount 2641 mg); one case of severe venous thrombosis (GA 35 weeks, total amount 400 mg for 2 d). Status at birth: All 12 newborns presented with severe hypoxemia which was associated in 3 cases with acute renal failure and anuna. Doppler echocardiography showed early ductal closure, pulmonary hypertension, right ventricle hypertrophy and right-to-left shunting through the PFO. Tricuspid regurgitation was present in 6 cases. Outcome: 8 babies survived: 2 recovered with oxygen only, 6 needed mechanical ventilation and pulmonary vasodilators, 3 NO, 1 ECMO. 4 babies died between days 3 and 11 with respiratory and heart failure preceding multiple organ failure. Post-mortem examination showed ductal closure, patent foramen ovale, pulmonary arteries dysplasia with muscular thickening. No relationship was found between cumulative dose of indomethacin and outcome. No baby died when the maternal treatment had been stopped for more than 12 days before delivery. Conclusion: As far as indomethacin therapy is needed during pregnancy, fetal Doppler echocardiography should be repeated and the treatment stopped in case of evidence of early ductal closure.