Single umbilical artery means that the umbilical cord vessels of the fetus have only one artery and one vein. Precautions for pregnant mothers include regular obstetric checkups and healthy diet. 1. Regular obstetric examination: Pregnant women found with single umbilical artery should undergo regular obstetric examination to observe whether there are other abnormalities, which may be accompanied by structural abnormalities of other organs at the same time. Commonly used examination methods include Down’s syndrome screening, ultrasound, non-invasive DNA, fetal chromosome testing and so on. 2. Healthy diet: in daily life pregnant women eat more high protein, high calcium food, such as beef, eggs, etc., not only can replenish the nutrition needed by pregnant women, but also can effectively help the baby grow healthily. In addition, single umbilical artery pregnant mothers also need to maintain a good mood, enhance their own resistance, etc., is conducive to fetal development. If there are other obvious malformations found in the fetus during the examination, it is recommended to seek timely medical treatment and take correct measures under the guidance of the doctor.