1. Principle and use of pregnancy test paper Pregnancy test paper is a simple and easy-to-use tool for detecting pregnancy. Its principle is to determine whether you are pregnant by detecting the presence of human chorionic villi (hCG) in the urine. The method of use is also very simple. You only need to place the test strip in the urine and wait for a few minutes to get the result. It should be noted that when conducting the test, the first urine urination in the morning should be selected because the concentration of hCG is highest at this time. 2. How to judge pregnancy test