Routine or selective ultrasound examinations in early pregnancy.
Two thousand fifty-four women were routinely screened with ultrasound in the tenth to 14th week of pregnancy. The clinical outcome was compared with a group of 1358 gravidas examined selectively with ultrasound. In the test group, 95% of all women had an ultrasound examination early in pregnancy; the corresponding figure in the control group was 50%. Neonatal outcome was similar, but the frequency of labor inductions decreased in the group routinely screened with ultrasound. Induction of labor for suspected postdatism increased the risk for emergency cesarean section in comparison with spontaneous onset of labor. In about 20% of all cases, prediction of the time of delivery was altered according to the ultrasound examination, and analysis of the patients with spontaneous onset of labor showed that ultrasound was a better predictor of the time of delivery than was the last menstrual period.