Routine ultrasound fetal examination in pregnancy: the 'Alesund' randomized controlled trial

Objective To evaluate the possible benefits of the routine use of ultrasoun d screening in pregnancy Design A randomized controlled trial was designed to detect a 50% differenc e in the incidence of induction for apparent post-term pregnancies between women who were screened with ultrasound and unscreened women. A total of 16 28 pregnant women from the general population were included. Eight hundred and twenty-five were allocated to air ultrasound examination at the 18th an d 32nd week of pregnancy in addition to receiving routine antenatal care. T he remaining 803 women received standard antenatal care, but could only be referred for ultrasound examination oil clinical indication. Results The incidence of induced labor due to apparent post-term pregnancie s was approximately 70% lower in the ultrasound-screened group. Inductions from all causes were also less frequent among ultrasound-screened women. Th ere were six perinatal deaths among the screened and seven among the contro ls after excluding three lethal malformations among the controls. There was no difference in Apgar score after 1 min, but the proportion with Apgar sc ore less than 8 after 5 min was lower among the screened group (P = 0.04). The need for positive pressure ventilation for mole than 1 min was lower am ong the screened group (P = 0.02). Birth weight was slightly higher in the screened group (39 g), but the difference was not statistically significant . Among the controls three pairs of twins remained undiagnosed until the mo thers were admitted to the hospital in labor at between 36 and 38 weeks ges tation. Conclusion These results suggest that for women who, were screened with ult rasound, obstetricians were less likely to induce label due to apparent pos t-term pregnancy, than for women who were not screened. All 10 pairs of twi ns in the screened group were diagnosed at the routine examination. These d ata also suggest that perinatal morbidity might be slightly lower in the sc reened group.