Predictive Capacity of a Chinese Birth Sex Chart

Abstract

Purpose: to test the predictive ability of a Chinese Birth Sex Chart.Setting: Provincial Prenatal Diagnosis Clinic for Advanced Maternal Age.Methods: case series of consecutive patients presenting for prenatal diagnosis on the basis of advanced maternal age. Comparison was made between the predicted fetal sex and the gold standard of fetal sex from cytogenetic testing. Degree of correlation was determined using Kappa statistics. Diagnostic test parameters of sensitivity and specificity were also determined.Results: Kappa values were found to be equal to 0.50, indicating only a moderate degree of agreement. As a diagnostic test, the Chinese Birth Sex Chart performs poorly with a sensitivity of 0.57 and a specificity of 0.46. Post-test likelihood calculations reveal only a minor degree of probability revision from using the Chart.Conclusions: while it does present a humorous diversion, the predicitive ability of the Chinese Birth Sex Chart is poor and, despite cultural pressures, it should not be used in reproductive decision-making.