In Reply.—I appreciate Dr Ryals' comments regarding the incidence of major congenital neurologic malformations that we recently reported.
Having spent many years as a military physician, I recognize that pregnant women known to be carrying fetuses with malformations are not infrequently referred to civilian hospitals. However, this has likely played a minimal role in affecting the results of our study. Only in the past 2 years has routine α-fetoprotein screening been performed on all pregnant woman in the major army medical centers, a period subsequent to the dates of the study. In addition, most of the smaller military hospitals do not have this capability. Furthermore, ultrasound study is not routinely performed on pregnant women. Although they have been commonly performed since the mid-1980s, the minority of women undergo ultrasound studies.
α-Fetoprotein levels in amniotic fluid have been evaluated since the mid-1970s. However, these evaluations were performed only in women with prior