Study of prenatal screening tests in pregnant women and comparison with fetal karyotype results

Abstract

Introduction:Regarding to the high prevalence of Down syndrome (1 per 700 births) different prenatal screening methods have been developed to identify high risk pregnant women. If the screening results were positive, prenatal genetic tests are recommended. This study was performed with aim to evaluate screening tests and comparison with fetal karyotype results. Methods: In this cross-sectional, descriptive and analytical study, the results of screening tests and genetic tests of 1009 pregnant women who underwent aneuploidy screening test in the years2015-2016, was examined. The information includes demographic data, familial history of previous child affected with Down syndrome, consanguineous marriage was obtained and then the results of screening and genetic test were recorded in a designed questionnaire. Data were analyzed using SPSS software (version 19), P value less than 0.05 was considered significant. Results: Based on the results of genetic tests, 59 cases (6) of the studied fetuses had aneuploidy that 41 cases had Down syndrome. There was a significant relationship between screening tests and aneuploidy (P<0.05), but there was no significant association between the risk of neural tube defect (NTD) and aneuploidy (p>0.05). Also, significant relationship was found between NT>3mm and aneuploidy (P<0.001). The sensitivity and specificity of NT test to aneuploidy detection obtained as 47 and 90, respectively. Conclusion: Fetal screening tests can help in finding pregnant women at risk for a child with chromosomal abnormalities. Further studies are recommended to determine the sensitivity of screening tests. © 2017, Mashhad University of Medical Sciences. All Rights Reserved.