Prenatal Screening for Chromosomal Abnormalities in Tabriz, North-West of Iran

Background : Several studies have indicated that when compared to non-consanguinous marriage, consanguinous marriage may lead to a higher incidence of congenital abnormalities. The study was performed to evaluate few screening tests to estimate the risk of chromosomal abnormalities in the first trimester compared between familial and non-familial marriages.
Materials and Methods : In this cross sectional study, 300 pregnant women with singleton pregnancy presenting to Tabriz Al-Zahra hospital from 2007 to 2009 were enrolled as study population. The participants were evaluated about chromosomal malformations using a combination of NT (Nuchal Translucency), PAPP-A (Pregnancy-Associated Plasma Protein A), and free beta- human chorionic gonadotropin (β-hCG). In positive screening test results, the participants underwent fetal karyotyping using amniocentesis or chorionic villi sampling (CVS).
Results : Pregnancies with higher risk were observed more among non-consanguineous marriages. The maternal age was not found to be a determinant in this regard. NT and free β-hCG values (but not PAPP-A) were significantly different between the two study groups. The triple screening test had a sensitivity of 100%. There were two cases of Down syndrome both belonging to the maternal age less than 35 years and non-consanguineous marriages.
Conclusion : Considering that a statistically significant association was not observed between abnormal test results and pregnancy complications (p=0.73), it seems that it is essential to use screening tests in all pregnant women. Especially that the only two pregnancies with Down syndrome in our study were under 35 years of age.