The occasional tugging pain in the abdomen in the fourth week of pregnancy may be a normal physiological phenomenon, or it may be a symptom of ectopic pregnancy or pre-miscarriage. 1. Normal physiological phenomenon: four weeks pregnant belly occasionally tugging pain, may be a normal physiological phenomenon. In the early stages of pregnancy, the pelvis will become congested and the hormone levels in the body will change, which will easily lead to uterine contractions causing discomfort such as lower abdominal cramps and back pain. 2. Ectopic pregnancy: if the patient in the early stages of pregnancy, obvious abdominal pain or unexplained vaginal bleeding, it may be ectopic pregnancy, need to go to the hospital as soon as possible to carry out the relevant checks, ectopic pregnancy need to end the pregnancy as soon as possible. 3. Pre-eclampsia: If there is frequent abdominal pain or even vaginal bleeding in early pregnancy, there may be pre-eclampsia, and the patient should go to the hospital for treatment as soon as possible. Pregnant women are advised to closely observe their own situation, if the pain is severe, lasts for a long time, or is accompanied by other discomforts such as vaginal bleeding, it is recommended to go to the hospital as soon as possible for examination.