P10.19: Down's syndrome screening at maternal age ≥ 35 years with non‐intervention examination at 11 − 13 + 6 weeks of gestation—a preliminary report

Abstract

To evaluate and present a non-intervention method for the screening of Down syndrome at maternal age ≥ 35 years, i.e. measurement of Nuchal Translucency thickness (with fixed cut-off NT ≥ 3.0 mm and CRL set at 50–70 mm) and Nasal Bone (NB) examination at 11–13 + 6 weeks of gestation This prospective study was conducted at 3 Hospital in Jakarta from January 2001 to January 2003. NT measurement was performed during this period. Combined NT measurement and NB examination was conducted from January 2002 to January 2003. Cases with NT ≥ 3.0 mm underwent TORCH examination, genetic amniocentesis was performed at 16 weeks of gestation for chromosome examination. Measurement of NT thickness was carried out in 175 cases obtained from 2001 to 2003. Combined NT measurement and NB examination was performed in 97 cases obtained from 2002 to 2003. Maternal ages ranged from 35 years to 43 years, with first to fifth gravidity. From the NT measurement in 175 cases, 7 cases had NT of ≥ 3.0 mm (3 cases with karyotype 47, XX, + 21, and 2 cases with karyotype 47, XY, + 21). Detection Rate (DR) of Down's syndrome was found at 71.4% with False Positive Rate (FPR) of 1.1%. From combined NT measurement and NB examination in 97 cases, 4 cases had NT of ≥ 3.0 mm, 3 cases showed absent NB (2 cases with karyotype 47, XY, + 21, and 1 case with karyotype 47, XX, + 21). With combined maternal age, NT and NB examination, DR of Down's syndrome was found at 87.5%, and FPR at 1.0%. This paper discussed the results of DR and FPR of Down's syndrome obtained from other investigators, case management with increased NT thickness and normal chromosome. Also discussed were attempts to increase DR of Down's syndrome, among other things, by combined examination NT, NB, MA, free β-hCG& PAPP-A, and the use of USG 3D.