Screening for Down’s Syndrome and Neural Tube Defect in Croatia

Objective: The purpose of this study was to investigate the efficiency of second-trimester maternal serum screening for Down’s syndrome and open neural tube defects using alpha-fetoprotein and free β-human chorionic gonadotropin as serum markers. Methods: 3,188 women underwent testing between 14th and 22nd week of pregnancy. Of all tested patients, 25.4% were ≥35 years old. A cut-off risk of ≥1:250 for Down’s syndrome and MS-AFP ≥2.0 MoM for open neural tube defect were considered screen-positive. Results: The detection rate for Down’s syndrome was 77.8% (7/9) with 8.2% screen-positive rate (7.9% false-positive rate). When evaluated separately, in patients younger than 35 and in those ≥35 years old, the screen-positive rates were 3.1 and 23.3%, respectively. A total of 52 (1.6%) were found screen-positive for open neural tube defect; 2 cases of encephalocela and 1 case of gastroschisis were confirmed prenatally. Conclusion: The respectable number of cases with trisomy 21 identified in this study confirms that routine mid-trimester screening for Down’s syndrome including MS-AFP, free β-hCG and maternal age is useful in identifying pregnancies at increased risk.