Objective: To analyze the clinical characteristics of patients with inflammatory bowel diseases (IBD) in pre-pregnancy, pregancy and loctation. Methods: The clinical data of pregnancy complicated with IBD in Department of Obstetrics and Gynecology of Peking University Third Hospital and deli-very from September 2011 to June 2022 were collected. The clinical characteristics of the patients were analyzed retrospectively. According to the state of diseases during pre-pregnancy, pregnancy and lactation, the patients were divided into active and remission group, and the two groups were compared interms of pre-pregnancy counseling, nutritional status, pregnancy and delivery complications, gestational week, mode of delivery, and neonatal outcome. Results: A total of 33 pregnant women with IBD were included in this study, of which 7 delivered a second child, for a total of 40 deliveries, with 36 natural pregnancies (90.0%) and 4 assisted reproductions (10.0%). Among the 40 cases, 21 cases (52.5%) were sustained in remission in pre-pregnancy, pregnancy and lactation, and 19 cases (47.5%) in disease activity, of which 8 cases (42.1%) were due to self-withdrawal of drugs or failure to take medicine regularly. Compared with the activity group, the disease remission group had a higher rate of pre-pregnancy counseling (57.1% vs. 15.8%, P=0.010), and higher levels of hemoglobin [(112.67±8.53) g/L vs. (102.84±5.23) g/L, P < 0.001], serum total protein [(66.58±6.34) g/L vs. (60.83±6.25) g/L, P=0.006], serum albumin [36.4 (35.1, 38.3) g/L vs. 34.3 (31.1, 35.6) g/L, P=0.006], serum calcium [(2.25±0.10) μmol/L vs. (2.13±0.15) μmol/L, P=0.004], but a lower incidence of gestational hypertensive disorders (0 vs. 31.6%, P=0.007). In 40 deliveries, there were 27 cases of vaginal delivery (67.5%), 13 cases of cesarean section (32.5%). The analysis of neonatal outcomes showed 38 full-term deliveries and 2 preterm deliveries; 1 case of macrosomia, 1 case of small-for-gestational-age, 1 case of low birth weight and 3 cases of birth defects. There were 10 newborns admitted to neonatal intensive care unit, including 4 cases of neonatal infections and 2 cases of neonatal jaundice. Conclusion: Pre-pregnancy counseling and evaluation of IBD patients are very important, and good pregnancy outcomes can be obtained through careful management during pregnancy in the most of the patients.