Vachirasrisoontra, Chalie, Wisude Anansakunwat, Chotima Suthantikorn, and Puangpayorm Prichakas. “Second Trimester Prenatal Screening for Down Syndrome in Thai Pregnant Women Using Alpha-fetoprotein and Free Beta-hCG”. Thai Journal of Obstetrics and Gynaecology 15, no. 2 (April 11, 2017): 69–77. accessed September 29, 2026. https://he02.tci-thaijo.org/index.php/tjog/article/view/82684.