Fetal anomalies: what is the diagnosis when the chromosomes are normal?

A retrospective study of cases of fetal anomalies associated with a normal karyotype was conducted (1) to evaluate the accuracy of prenatal diagnosis; and (2) to assess two different tools to assist in determining the correct diagnosis. A total of 201 charts were reviewed. The accuracy of the prenatal diagnosis was assessed subjectively by one physician. The London Dysmorphology Database and a locally developed non-computerized tool (Appendix) were assessed retrospectively using 36 test cases. The population studied presented a spectrum of 97 different groups of single (67%) or multiple (33%) anomalies. The prenatal diagnosis was accurate in 57% of the cases. The two proposed tools generated an average of 146 and 15 different diagnoses, respectively and the correct one in 26 and 22 of the 36 test cases. The two studied tools have the potential to generate a differential diagnosis in the presence of a fetal anomaly prior to and following normal karyotype analysis. The non-computerized tool presents the advantages of listing antenatal features and creating a shorter differential diagnosis list with a minimal decrease in the identification rate of the correct diagnosis. Its use should be studied prospectively.