The authors have made the census of all the Medical Terminations of Pregnancy (MTP) which have been carried out in the Department of Ille et Vilaine from 1982 to 1986, i.e. 222 cases, in order to precise the different indications and the diagnosis tools which were used. 132 MTP concern women who live in the Department of Ille et Vilaine. By referring this figure to the total number of pregnancies in this area, one can see that the average incidence is of 1.9%; MTP account for 1% of the total number of Terminations of Pregnancies. Foetal indications are more frequent (188 cases; i.e. 84.7%) than maternal ones (34 cases, 15.3%); these figures remained stable over the 5-year period of study. Chromosomal aberrations and closing defects of the neural tubule are the main causes of MTP (22.9% of foetal indications). Among the 43 chromosomal aberrations, trisomies are the most frequent ones (34.9%) because all women aged 38 or more are proposed a detection. The diagnosis of trisomy was made in 24 cases after tests were programmed either because of the age of the mother or because of family antecedents (amniocentesis: 22 times, punction of foetal blood: once, biopsy of chorion villosities: once), in 6 cases after tests were carried out on the basis of suspect clinical signs amniocentesis: once, punction of foetal blood: 5 times), and in 13 cases after the echography had revealed a major syndrome. Closing defects of the central nervous system mainly concern anencephaly (17.6% of foetal indications) since the echography enables an easy diagnosis. All anencephaly have actually been detected during the reference period of pregnancy.(ABSTRACT TRUNCATED AT 250 WORDS)