[Rate of spontaneous abortion in relation to the time of fetal viability assessment].

For the first time, the rate of spontaneous abortion is reported in a multicenter study of three different gynecological centers. In 1987 und 1988, the average spontaneous abortion rate in 315 pregnancies was 3.3%, after foetal heart actions had been verified by ultrasonic examination between the 7th and 12th week of gestation. A statistical significance has been calculated between the spontaneous abortion rate of 6.3%, if foetal heart beats were seen between the 7th and 9th week, and the spontaneous abortion rate of 1.0% with an evidence of foetal life (p less than 0.01) between the 10th to 12th week of gestation. The rate of spontaneous abortion of women above 34 years of age (8.9%) is statistically different (p less than 0.01) to that of women under 35 (1.9%). In women older than 34, the spontaneous abortion rate before the 10th week of gestation is 22.2% in contrast to 3.2% of women younger than 35 (p less than 0.01). Considering the evidence of foetal heart actions between the 10th and 12th week, the spontaneous abortion rate of women above the age of 34 is 1.9%, compared to 0.8% of women younger than 35. The statistical higher spontaneous abortion rate of women above the age of 34 before the 10th week of gestation and the lack of statistical difference of the abortion rate in this defined age group for foetal life to be proven from the 10th week on, should be an argument in favour of the 10th week of gestation as the earliest date of prenatal diagnosis.(ABSTRACT TRUNCATED AT 250 WORDS)