[Early echography subprogramm.  Southern Metropolitan Health Service evaluation 1989-1990]. 
The results of an early level I ultrasound program performed in the Southern Health Area of Santiago during the years 1989 and 1991 are reported.  It was noticed that suspect gestational age constituted the highest number of ambulatory attentions (23.9%) in the High Risk Obstetric Department of Barros Luco Trudeau Hospital in 1987.  With this program, in 1990, 82% of pregnant women were examined before 20 weeks' gestation, with a total of 10447 ultrasound examinations.  Suspect gestational age descended to 8.6% in 1990 (compared with 23.9% in 1987).  Amniocentesis and amnioscopies also diminished abruptly.  The value of early routine level I ultrasound program in obstetric population improves maternal, fetal and newborn health indexes.  These conditions are discussed.