The relationship of threatened abortion to fetal abnormalities

There were 289 infants with congenital defects, or 2.42 per cent of 12,000 consecutive infants delivered at the Evanston Hospital. Of these 289, there were 110, or 0.92 per cent of 12,000, who had major abnormalities; 179, or 1.5 per cent exhibited less severe defects. It is estimated that there were at least 800 cases of threatened abortion in these 12,000 cases. The incidence of major fetal defects in the threatened abortion group is no more than 1.5 per cent. This is slightly greater than the incidence of defective infants in the group which did not threaten to abort. In clinical terms, however, the data give an expectancy of normalcy in 97 out of 100 infants whose mothers have threatened to abort. The incidence of abnormal infants in the series does not significantly differ from local and national averages covering years previous to attempted specific treatment of threatened abortion. It would seem, therefore, unlikely that attempts to save threatened abortions increase the frequency of abnormal babies.