Some epidemiological data on spontaneous abortion in Hungary, 1971-80.

A population based survey of women who had spontaneous abortion in Hungary between 1971 and 1980 has been evaluated. Individual data sheets completed by specialists in obstetrical institutions were used. The ratio of spontaneous abortions was 13.1% during the whole period studied but declined during the decade. The maximum occurrence was in the fifth to eighth week of gestation, when more than 40% of all spontaneous abortions occurred. Thereafter spontaneous abortion ratios decreased gradually with duration of pregnancy. The distribution of spontaneous abortions by calendar month shows characteristic seasonal changes, the minimum values being found from April to July whereas the maximum values were from October to February. The spontaneous abortion ratios increased significantly with the age of mother, over age 40 it approached 50%. They also increased with the pregnancy order, a minimum figure being registered at the first pregnancy of women in their 20s. The risk for women with a history of spontaneous abortion was 33%.