Objective To evaluate a prenatal questionnaire as a genetic screen and as an aid in pre-amniocentesis genetic risk assessment.
Methods In a retrospective cohort study, charts were reviewed for 158 consecutive women of advanced maternal age referred for genetic counseling. Genetic risks identified by use of a questionnaire completed by 79 consecutive patients were compared with those risks identified by the referring physician, those identified during subsequent three-generation pedigree analysis, and to genetic risks identified by pedigree evaluation of 79 consecutive individuals who underwent genetic counseling without the aid of a questionnaire (controls).
Results Sixteen (20%) of the questionnaires revealed a previously unidentified genetic risk. The sensitivity and specificity of the questionnaire were determined to be 40.0 and 97.4%, respectively. Pedigree analysis alone (control group) identified significantly more at-risk pedigrees than did the questionnaire alone (34 versus 20%, P <.05), but identified significantly fewer at-risk pedigrees than obtained from the study group patients who completed a questionnaire and pedigree evaluation (34 versus 50.6%, P <.05). Of all 158 patients, 15.2% (n = 24) underwent additional testing on the basis of genetic risk assessment. There was no difference between the study and control groups in additional evaluations performed (P = 1.0).
Conclusion A three-generation pedigree is superior to a questionnaire in genetic risk assessment. The questionnaire was not sufficiently sensitive to serve independently as an adequate genetic screen or risk assessment tool and did not influence subsequent fetal evaluation. Assessment of the sensitivity and specificity of prenatal genetic questionnaires should be undertaken before their routine clinical use.
Address reprint requests to: Gabriel M. Cohn, MD, Department of Obstetrics and Gynecology, Baystate Medical Center, 759 Chestnut Street, Springfield, MA 01199.
© 1996 The American College of Obstetricians and Gynecologists