[Surgery in utero on a two-headed monster. The value of echography]

A binovular triplet pregnancy with a normal fetus and bicephalic monster was diagnosed by ultrasound after 19 weeks of amenorrhoea. After selective amniocentesis and genetic studies the diagnosis led us to kill the double monster in utero by injecting hypertonic saline into its aorta. The healthy twin went on growing normally in the following weeks. Premature vaginal delivery resulted in the expulsion of a macerated double monster and the birth of a baby weighing 1,650 g in blood health. This case history leads us to discuss the value of ultrasound in multiple pregnancies and the ability to carry out intra-uterine procedures in these special cases.