An Engineer Looks at Bayes

Abstract

As a proportion of total abortions, those performed in the second trimester declined from 21% in 1974 to 10% in 1991. Second trimester (13 to 24 weeks) abortions were more frequent among women who were single, under age 20, and without prior deliveries or abortions. The stage of pregnancy at which an abortion was performed and the method used were associated with the risk of medical complications. Complication rates increased directly with the period of gestation. The complication rate for second trimester abortions was 13 times higher than that of first trimester abortions (under 13 weeks). The lowest complication rates were found among abortions performed using surgical D&C and suction D&C. The procedures primarily used for abortions at 16 or more weeks' gestation (i.e. the administration of prostaglandin, urea or saline) were associated with higher complication rates.