The small abdominal pain like period pain at 4 weeks of pregnancy may be due to physiological factors or disease factors. It is recommended to visit the obstetrics department of the hospital in time for ultrasound, blood HCG and other examinations, and treat the cause according to the examination results. Common causes and treatment a. Physiological factors: small abdominal pain at 4 weeks of pregnancy may be due to the increasing size of the uterus and compression of the ligaments around the uterus. If there is no bleeding or other symptoms, you can take appropriate bed rest, avoid straining and strenuous activities, and observe whether the symptoms are relieved. If the symptoms of abdominal pain continue to worsen or other symptoms such as bleeding appear, you should go to the hospital in time to find out the cause. Second, disease factors: 1. Pre-eclampsia: It can be manifested as a small amount of vaginal bleeding with lower abdominal pain, which may be similar to the feeling of period pain. Strict bed rest is recommended, and if necessary, hospitalization can be received for fetal preservation treatment; 2. Ectopic pregnancy: small abdomen like period pain, vaginal bleeding, and unilateral lower abdominal tearing-like pain may occur. It needs to be judged by ultrasound examination, blood HCG, clinical manifestations and other comprehensive judgments. In stable cases, when the HCG level is low and on a decreasing trend, interventions can be dispensed with and the pregnancy can be reviewed regularly at the hospital and wait for its natural abortion or absorption. Methotrexate and mifepristone can also be used for early ectopic pregnancy. If necessary, tubectomy or conservative surgery can be performed to remove pregnancy products; 3. Embryonic abortion: If embryonic abortion occurs, the pregnant woman will no longer have early pregnancy reactions such as nausea and vomiting, there will be vaginal bleeding, often dark red bloody leucorrhea, excess vaginal bleeding when inevitable abortion occurs, and lower abdominal pain may also occur. It is recommended to seek medical treatment in time, and if necessary, to do the treatment of uterus removal; 4. Uterine fibroid degeneration: If pregnant women suffer from uterine fibroids, when the fibroids occur red degeneration can produce abdominal pain symptoms, similar to menstrual pain, or even more serious. It is recommended that the treatment should be comprehensive according to the condition of the pregnant woman and the fetus, so as to preserve the fetus to the maximum extent; 5. ovarian cysts: if ovarian cysts appear after pregnancy and twist, they can suddenly cause severe pain in the lower abdomen, accompanied by nausea and vomiting, and the pain is similar to the pain of menstruation. When a small cyst or simple plasmacytoma ruptures, the symptoms of abdominal pain like menstrual pain may also occur. When a large cyst or teratoma ruptures, there is often severe abdominal pain, nausea, and vomiting. In case of ovarian cyst torsion, immediate surgery should be performed to remove the cyst. In case of ruptured ovarian cyst, depending on the nature of the cyst, the size of the cyst and rupture, the extent of ascites and bleeding, the specialist will decide whether to operate urgently. If the abdomen is like a period pain in the 4th week of pregnancy, in addition to medical treatment, the pregnant woman should pay attention to her diet and avoid eating cold, spicy and stimulating food to avoid aggravating the abdominal pain. The abdominal pain can be relieved by drinking more hot water and keeping warm.