To the Editor: Ewigman et al. (Sept. 16 issue)1 attempted to determine the efficacy of ultrasonography in pregnancy, but their methods obscured the issue of routine scanning. Of 55,744 women registering for obstetrical care, the authors excluded 32,317 (58 percent). Another 7897 (14 percent) were lost to follow-up or declined to participate in the study. Thus, of all the women, only 15,530 (28 percent) were actually studied. Of the half assigned to the control group (14 percent of the initial cohort), 45 percent underwent ultrasonography. The authors provided no data to explain why the women in this group underwent scanning.
|Number of pages||3|
|Journal||New England Journal of Medicine|
|State||Published - Feb 24 1994|