[Spontaneous abortion in women: cytogenetic and epidemiological studies]

Chromosome anomalies are often found in ova expelled spontaneously. The proportion of ova affected varies with the sampling conditions. A great variety of anomalies were distinguished. The authors studied in turn : monosomies, trisomies, polyploid types double aberrations, mosaics, and structural anomalies. The frequency of the anomalies was studied in relation to the duration of the pregnancy and the duration of the development of the ovum. Among the factors studied, maternal age was correlated only with the cases of trisomy. The age of the gametes seemed to be of great importance. It was difficult to determine the effect of oral contraceptives but they did not seem to be important. In contrast, ovulation inducers were implicated. As regards to the effects of irridiation, the incidence of anomalies appeared to be increased by radiography before pregnancy and by irradiation to which the husband was exposed at his place of work. The previous obstetric history makes it possible, to a certain extent, to forecast the risk of genetic abortion and it is possible to calculate statistically that the number of anomalous embryos conceived is practically identical to the number of normal infants born.