Second Trimester Screening for Down and Edward Syndromes Using Biochemical Markers of Mothers

The main objective of the present study was to evaluate the efficacy of second trimester screening for Down syndrome and trisomy 18 in a population of pregnant women in east Azerbaijan province. The study involved 300 consecutive women who attended the screening between the 15th and 20th weeks of pregnanc. A blood sample was obtained to measure alpha feto protein (AFP), intact human chorionic gonadotropin (hCG) and unconjugated estriol 3 (UE3). The combined risk assessment including maternal age, AFP, hCG and UE3 was performed in each individual using a computerized risk figure program. The positive screen results were referred to prenatal diagnosis to prenatal diagnosis clinic for further molecular and cytogenetic studies. The mean age in study population was 25.11±5.47 years. Twenty one positive screen results (7%) were detected for Down syndrome and 9 positive screen results were detected for Edward syndrome (3%). The mean age in these groups were 30.62±7.88 and 30±4.26 years respectively. The remaining 270 individuals had negative screen results and the mean age in this group was 24.75±5.45 years. Prenatal diagnosis using interphase Fluorescence in Situ Hybridisation and standard cytogenetic techniques revealed Down syndrome in 3 positive screen results (7%). Two positive screen pregnancies for Down syndrome were terminated due to fetal death. In none of the positives screen results for trisomy 18, Edward syndrome was confirmed through the aforementioned techniques. The results of this study were comparable to the previous studies. These showed that second trimester study of pregnant mothers is a useful screening model for detection of Down syndrome.