In clinical work, we often encounter pregnant women who say that they have significant pain on the left side of the abdomen, in this case, it is necessary to deal with different causes of the possible, some cases are more serious, and some cases are finishing line of pain. Causes of left-sided abdominal pain in early pregnancy: 1, ectopic pregnancy: left tubal pregnancy may cause severe pain on the left side, in which case emergency surgery or hospitalization is required. 2, normal pulling pain: uterine enlargement caused by pulling the left side of the round ligament, observation and rest can be, the pain is usually not serious. 3, Pre-eclampsia: often accompanied by bleeding and requires appropriate use of medication. Causes of left-sided abdominal pain in late pregnancy: 1, placenta abruptio: placenta abruptio from the left uterine wall, obvious abdominal pain, often stillbirth and coagulation abnormalities. Treatment: anti-shock, correction of coagulation abnormalities, early evacuation of the uterus. Choose vaginal assisted delivery or cesarean delivery according to the situation 2. Uterine rupture: severe abdominal pain, non-relaxation between contractions, change of fetal heartbeat, unsatisfactory descent of fetal previa, reduction of uterine opening; hematuria, bright red vaginal bleeding, etc. Emergency cesarean section is needed. The rupture on the left side is often manifested as left-sided abdominal pain. 3. Intrauterine infection: premature rupture of fetal membranes, abdominal pain, fever, odor of vaginal discharge, and change of fetal heartbeat. Anti-inflammatory and termination of pregnancy. Among the possible causes that may be present throughout pregnancy: 1. Left ovarian cyst: During pregnancy, a large cyst may rupture or cause ovarian torsion, producing severe abdominal pain and thus increasing the risk of miscarriage or preterm delivery. Therefore if the cyst size does not spontaneously decrease after a few weeks large cysts (more than 6-8 cm) are usually surgically removed. 2, fibroids: Most fibroids are small and patients are asymptomatic; however, when it increases in size, it may cause pelvic pressure, abdominal pain, deformation of the uterine wall or endometrial cavity, and lead to abnormal uterine bleeding, and the presence of fibroids in early pregnancy increases the risk of miscarriage. 3. Left-sided urinary tract infection and urinary stones: Left-sided urinary tract infection is common during pregnancy, and patients often present with frequent urination, urgent urination, painful urination and lower abdominal pain. Urinary stones are also a common cause of abdominal pain in hospitalized pregnant women. Key tip: Identify the cause and target treatment. Focus on prevention!!!