Broken amniotic fluid can be detected with pH test paper, which usually shows a blue color. The pH test paper is mainly used to detect the different acidity and alkalinity of the solution, the test paper contains methyl red, bromocresol green, thymol blue three kinds of indicator, these three kinds of indicator in different pH value of the solution will appear color change, in the alkaline solution under the action of the test paper will generally become blue, amniotic fluid is alkaline solution, so the test paper with pH test paper to detect amniotic fluid test paper will turn blue. However, there is a certain degree of error in the detection of amniotic fluid with pH test paper. If rupture of amniotic fluid is suspected, it is necessary to go to the hospital in time to confirm the diagnosis through the measurement of the pH of the vaginal fluid, vaginal fluid smear, ultrasound, amnioscopy, etc., and then carry out the relevant treatments.