I. Intestinal obstruction Intestinal obstruction is the third common non-obstetric cause of acute abdomen in pregnant women, with an incidence of approximately 1 in 1500-1600 pregnancies, especially in women with a history of previous abdominal surgery and peritonitis. 25% of pregnant women with intestinal obstruction have intestinal torsion, but less than 1% of non-pregnant patients. The risk of appendiceal torsion increases as pregnancy progresses, particularly during the rapidly enlarging uterus from 16 to 20 weeks, when the uterus enters the abdominal cavity, as well as during 32 to 36 weeks when the fetus enters the pelvis and after delivery when the uterus becomes rapidly smaller. Small bowel torsion accounts for approximately 9% of pregnancies. Other rarer conditions, including intussusception, strangulated hernia, cancer, and diverticulitis account for 5% of cases. Symptoms of intestinal obstruction are consistent with the normal population and include cramping abdominal pain, bloating, nausea, vomiting, and cessation of bowel movements. However, symptoms may be diminished or atypical in pregnant women, so when faced with a pregnant woman with refractory vomiting, it is important to rule out the possibility of intestinal obstruction, especially during the first trimester of pregnancy. In pregnant women with symptoms of obstruction, 82% of standing abdominal plain films demonstrate dilated small bowel collaterals and dynamic air-fluid flattening, and the sensitivity of standing abdominal plain films to diagnose intestinal torsion is 95%. If there are no typical signs of intestinal obstruction on abdominal plain film, further examination with enhanced CT or oral contrast followed by abdominal plain film is mandatory. The risk of radiation exposure to the fetus is much lower than the risk of complications and death to the mother and fetus. For cecum torsion without serious complications, colonoscopy may help improve symptoms, but much less than for sigmoid torsion. Surgical treatment should not be delayed and treatment decisions should be made in the same way as in the non-pregnant population. Unless clinical, laboratory, and imaging evidence of increasing obstruction exists, medical treatment should first include gastrointestinal decompression, hydration, and electrolyte replacement. Failure of medical therapy or worsening symptoms, such as fever, tachycardia, and markedly elevated white blood cells in combination with severe abdominal pain, require immediate surgical intervention. Trans-abdominal median incision open surgery is recommended, the height of which should be determined by the size of the uterus. Acute pancreatitis The incidence of acute pancreatitis in pregnant women is about 0.3-1/1000. 80% of acute pancreatitis in the normal population is caused by gallstones or alcohol consumption (the proportions are about the same for both). In pregnant women, 67-100% of acute pancreatitis is caused by gallstones and 4%-6% is caused by hypertriglyceridemia. Acute pancreatitis usually occurs in the sixth to ninth month of pregnancy. Acute pancreatitis in pregnant women is more difficult to diagnose. The typical symptoms of acute pancreatitis, including sudden onset of epigastric pain radiating to the back, postprandial nausea and vomiting, with or without fever, are the same as those of severe obstetric emergencies such as retroplacental hematoma, complications of pre-eclampsia, or the presentation of HELLP syndrome, which requires emergency cesarean delivery. A threefold increase in lipase level strongly supports the diagnosis of acute pancreatitis. Ultrasound is the main diagnostic tool for acute pancreatitis, complemented by MRI to further assess the severity of the disease; prophylactic antibiotics must be considered in severe cases (beyond Balthazar score stage D). Management is the same as in the non-pregnant population and should be admitted to the intensive care unit with intravenous fluids, electrolyte and vitamin supplementation, and monitoring of the fetal heart rate. Treatment is effective for most pregnant women and diet can be started on the fourth day. The management after the acute phase should be more careful and thorough, and should be tailored to the different stages of pregnancy, mainly because the recurrence rate of acute biliary pancreatitis in pregnant women is 70% (90% of which occurs after the first hospitalization), while in the normal population it is only 20-30%. During the first trimester, surgery should be avoided and laparoscopic cholecystectomy can be considered in the third to sixth months of pregnancy. In the 6th-9th months of pregnancy, performing sphincterotomy under ERCP is a safe and effective treatment, and laparoscopic cholecystectomy can be performed until after the birth of the baby. In fact, the rate of preterm delivery is almost 0 when cholecystectomy is done in the 3rd-6th months of pregnancy, but up to 40% when it is done in the 6th-9th months. With the improvement of early diagnosis and neonatal care, the perinatal mortality rate is lower than 5%.