2,648 sonograms were performed in a continuous series of 1,000 patients, all of whom had delivered in the department between March 1, 1988 and September 1, 1988; pregnancies resulting in a spontaneous miscarriage, extra-uterine pregnancy, therapeutic abortion as well as invasive sonographies, are excluded. Most patients underwent two or three sonograms during their pregnancy. 74 per cent of the requests come from specialists. The main indications are either systematic (67.7%) or result from early manifestations (25.1%). 12.6 per cent of the sonograms are performed before 12 weeks of amenorrhea, including 36.7 per cent performed systematically, and could be performed at a later date. 90 per cent of the term modifications were correctly indicated, and there were early manifestations in 60 per cent of the cases. 45.1 per cent of intra-uterine growth delays were detected and there were early manifestations in 50 per cent of the cases. 41.6 per cent of the malformations were diagnosed on sonograms. Renal malformations are easily recognized; this is not true of cardiac malformations. 96 per cent of the patients were justifiably reassured or worried. Ultrasonography presents a good sensitivity for term modifications, macrosomia, placental insertion anomalies. The sensitivity is less for intra-uterine growth delays and fetal malformations.