Medical - Journal of Nutrition & Health https://www.avensonline.org/ Analysis of Pregnancy Testing Index Results in Miyun District, Beijing from 2017 to 2021 https://www.avensonline.org/fulltextarticles/JNH-2469-4185-08-0042.html 01 July, 2022 Lu Yu, Gaiyan L, Jinxin G, Hongmei X, and Ting L