Anesthetic management during a laparoscopic splenectomy in a third trimester pregnant patient with idiopathic thrombocytopenic purpura (ITP) is critical because of the possibility of massive intra- and postoperative bleeding either maternal, fetal, or both. Laparoscopic surgery may be beneficial in pregnant patients compared to open laparotomy, but the safety of laparoscopic operations in pregnant women is under investigation. Pregnancy, especially in the third trimester, has been considered a contraindication of a laparoscopic procedure because the effect of CO2 pneumoperitoneum on the fetus and uterine blood flow is unclear. However, the benefits of laparoscopic surgery such as less stress response and a shorter hospital stay are postulated. The careful anesthetic management and close hemodynamic monitoring of patient and fetus will be helpful in making laparoscopic surgery safer in pregnant patients. We report on the anesthetic management during a laparoscopic splenectomy in a third trimester pregnant patient with ITP. We monitored the intestinal mucosal CO2 using Tonocap because we considered it could sensitively represent the uterine perfusion and intestinal CO2 status, and we also monitored the noninvasive cardiac output by using NICO . Although the arterial and intestinal mucosal CO2 tension, PrCO2 and CO2 gap increased gradually during the operation, hypercapnia was not remarkable. Tonocap represented the earliest changes which made us control intraabdominal gas inflation pressure by detecting fluctuations of CO2 gap and pHi even though other respiratory and monitored hemodynamic parameterswere quite stable during the procedure in this case. The patient was maintained well postoperatively and discharged with an improved condition. She had preterm labor at 36 weeks and 4 days of eventful gestation, but safely delivered a healthy baby by a normal spontaneous method.