Occasional vague pain in the small of the abdomen at 5 weeks of pregnancy may be caused by the pregnancy itself. As a result of the gradual development of the fertilized egg after its implantation, the uterus enlarges, which leads to vague pain in the small abdomen. As long as it does not interfere with daily life, treatment is usually not necessary. Because this is a normal physiological phenomenon, rest in bed and reduce unnecessary activities. Also be careful not to have sexual intercourse to avoid miscarriage. If the vague abdominal pain continues to increase and there is pain in the abdomen or vaginal bleeding, it is a sign of preterm abortion. In this case, it is necessary to go to the hospital and apply fetal preservation drugs if necessary. In early pregnancy, it is important to pay attention to the supplementation of trace elements and folic acid to ensure the normal development of the gestational sac and also to prevent neural tube abnormalities in the fetus, and to go to the hospital for regular maternity checkups.