The third trimester of pregnancy is already in the middle of pregnancy, and a mother and child health handbook is required. The obstetrician needs to report if the pregnancy risk level is yellow or above. Routine maternity checkups include: i. Measurement of height and weight, and calculation of body mass index to guide nutritional intake during pregnancy, and attention to controlling weight gain. Second, measure blood pressure, blood pressure testing is a mandatory item in every maternity checkup, if there is elevated blood pressure, timely intervention should be made. Third, listen to the fetal heart, in the third trimester of pregnancy when the uterus increases to out of the pelvic cavity, at this time in the obstetric examination can be above the pubic symphysis to feel the bottom of the uterus, and through the Doppler fetal heart stethoscope, in the abdomen can be heard in the fetal heart, to monitor the number of times the fetal heart is regular. Fourth, the most important thing in the third month is to do NT under the ultrasound, NT is the thickness of the fetal nuchal translucency, if the NT value is greater than 2.5mm, the fetus has the risk of Down’s syndrome and congenital heart disease risk, and need to be further examined.