ANALYSIS OF FETAL SEX IN TCC SAMPLE DNA - A CONTRIBUTION TO THE VALIDATION OF THIS APPROACH

We compared two methods of collection of transcervical cell samples, m ucus aspiration and cytobrush, with respect to the efficiency in deter mining fetal sex and we correlated the results with the week of gestat ion (7-11 weeks) to evaluate if the age of gestation influenced the su ccess of the analysis. DNA extracted from TCC samples recovered by muc us aspiration (n = 27) and cytobrush (n = 36) were analysed by nested PCR to predict fetal sex. The statistical indices of sensitivity, spec ificity, positive predictive value and negative predictive value were determined, and compared with those of other studies previously perfor med. No statistically significant difference was found between the two methods of TCC sampling concerning the success of fetal sex predictio n which was high for both methods (78 per cent and 89 per cent) and no correlation with the week of gestation was found. Transcervical cell sampling represents an encouraging prospect for first-trimester prenat al diagnosis even when the least invasive techniques are used. (C) 199 8 John Wiley & Sons, Ltd.