The official journal of the Japan Atherosclerosis Society and the Asian Pacific Society of Atherosclerosis and Vascular Diseases Case Report Hypertriglyceridemia (HTG) is a state of increased serum triglyceride (TG) affected by multigenetic and multifactorial causes. Serum TG concentration can be markedly elevated if exposed to precipitating factors, such as estrogen hormone and pregnancy. We report the case of a patient with severe HTG who suffered from recurrent pancreatitis during the second trimester of pregnancy conceived with in vitro fertilization-embryo transfer (IVF-ET) and was successfully controlled by multiple sessions of plasmapheresis.A 24-year-old pregnant woman was admitted because of a sudden onset of severe abdominal pain at 26 weeks of gestation conceived by IVF-ET. She has experienced recurrent pancreatitis despite low-fat diet and dyslipidemia medications allowed in pregnancy. At admission, serum amylase and lipase were elevated to 347 and 627 U/L, respectively, along with fasting TG to 4809 mg/dL. A clinical diagnosis of HTG-induced acute pancreatitis was made, and plasmapheresis was performed. After plasmapheresis, serum TG, amylase, and lipase levels decreased to 556 mg/dL, 60 U/L, and 69 U/L, respectively, along with subsequent pain relief. The patient underwent a total of nine sessions of plasmapheresis to retain serum TG lower than 1,000 mg/dL during pregnancy, with no further recurrence of acute pancreatitis. After delivery, the serum TG level was maintained below 500 mg/dL with a combination treatment of fenofibrate, statin, and ezetimibe.Although severe HTG is usually asymptomatic, if exposed to precipitating factors, it can cause acute pancreatitis, a fatal complication. Early application of plasmapheresis may be a useful option in HTG-induced acute pancreatitis intractable to medical treatment; however, its indications, risks, and benefits should be carefully evaluated. therapy, and drugs 4) .TG level elevation was related to estrogen level changes [5][6][7] . Although the mechanism is unknown, oral contraceptive or in vitro fertilization-embryo transfer (IVF-ET) is also known to increase TG level and cause acute pancreatitis [8][9][10][11] . Regarding pregnancy, studies have investigated clinical courses related to HTG and HTG-induced acute pancreatitis [12][13][14] . In consideration of IVF-ET, currently reported cases are focused on HTG-induced acute pancreatitis before Copyright©2021 Japan Atherosclerosis Society This article is distributed under the terms of the latest version of CC BY-NC-SA defined by the Creative Commons Attribution License.