There are not many pregnant women with a single umbilical artery. One of the ultrasound examinations during pregnancy is to check the number of umbilical artery strips. Most fetuses have 2 umbilical arteries, while a small number of fetuses have only 1 umbilical artery, called single umbilical artery. The pregnant woman usually does not feel anything, and there may be partial effects on the fetus. Normally, two umbilical arteries deliver nutrients to the fetus, but if there is a single umbilical artery, one umbilical artery is missing to deliver nutrients to the fetus, which may cause fetal stunting, delayed growth, or even premature birth. Therefore, pregnant women with single umbilical artery need to pay attention to the following matters: 1. regular maternity checkups: especially pay attention to the results of Down’s syndrome screening, NT test and non-invasive DNA, if no other abnormalities are found in the later review, normal maternity checkups can be done; 2. self-counting fetal movements: fetuses with single umbilical artery are more prone to hypoxia than normal fetuses due to the lack of a nutrient delivery pipeline, so it is necessary to strictly self-count fetal movements in late pregnancy to get a general idea of fetal growth and development through fetal movements. The fetal growth and development can be understood to ensure the safety of the fetus and avoid the occurrence of intrauterine hypoxia.