1992 Volume 19 Issue 1 Pages 66-74
The incidence of habitual aborters and the abortion rates of their next untreated pregnancy are difficult to estimate because the habitual aborters(those who have aborted more than three times successively)rarely continue their pregnancy without being treated. This information is indispensable to obstetricians who treat the patients with a new treatment and evaluate its efficacy. The method of moments and the maximum likelihood method are used to estimate these parameters based on a simple model about the habitual abortions. The abortion rates of the third and fourth pregnancy of habitual aborters with three consecutive abortions were0.306and0.313respectively according to thetwo-causes group model, which are smaller than the observed rates.The abortion rate of the fifth pregnancy was 0.314according to the two-auses group model and0.472according to the three-causes group model.