Pregnant women with a single umbilical artery have normal Down’s syndrome screening and are recommended to undergo noninvasive DNA testing. Single umbilical artery alone does not increase the risk of chromosomal abnormality, and the risk of chromosomal abnormality in the fetus is increased when the single umbilical artery is combined with fetal malformations. The accuracy of Down’s screening for trisomy 13, trisomy 21, and trisomy 18 is about 60%, whereas the accuracy of non-invasive DNA screening is 99.9%. Therefore, it is still recommended to complete non-invasive DNA testing for a single umbilical artery even if Down’s screening suggests that it is normal. When the ultrasound indicates that the fetus has a single umbilical artery, it is recommended to consult an obstetrician in time and take the next step under the guidance of the obstetrician, as well as conduct regular obstetric checkups to monitor the growth and development of the fetus.