Objectives: The aim of study is to determine the sensitivity and specificity of screening for fetal trisomy 21 in the first trimester of pregnancy using a combination of maternal serum biomarkers and ultrasonography. The objectives of this study were to first duplicate and confirm within the Mongolian population. the results of other similar studies. Our results corroborated closely w... https://www.bekindtopets.com/super-value-Keychron-M4-Wireless-4K-Mouse-flash-choice/