ObjectiveTo investigate the efficacy and safety of endoscopic retrograde cholangiopancreatography （ERCP） during pregnancy and puerperium through a comparative analysis. MethodsA retrospective analysis was performed for the clinical data of 22 patients in pregnancy and 39 patients in puerperium who received ERCP in Digestive Endoscopy Center of The First Affiliated Hospital of Nanchang University from January 2007 to August 2022. The two groups of patients were compared in terms of baseline data， diagnosis during ERCP， interventions， laboratory results before and after ERCP， post-ERCP complications， and delivery and fetal outcomes. The independent-samples t test was used for comparison of continuous data between two groups， and the chi-square test or the Fisher’s exact test was used for comparison of categorical data between two groups. ResultsThere were no significant differences between the patients in pregnancy and those in puerperium in all baseline data （all P>0.05） except the rate of CT examination （22.73% vs 58.97%， χ²=7.44， P=0.006）. During the ERCP procedure， compared with the patients in puerperium， the patients in pregnancy had a significantly lower proportion of the patients who underwent biliary stone extraction or endoscopic papillary balloon dilation （χ²=4.007 and 4.315， both P<0.05） and a significantly higher proportion of the patients who did not receive X-ray fluoroscopy （χ²=12.103， P=0.001）. After ERCP， both groups had significant improvements in white blood cell count， total bilirubin， direct bilirubin， alanine aminotransferase， and aspartate aminotransferase （all P<0.05）. The overall incidence rate of post-ERCP complications was 7.04% （5/71） for all patients， with post-ERCP biliary infection as the most common complication （3/71，4.23%）， and there was no significant difference in the incidence rate of post-ERCP complications between the two groups （P>0.05）. As for delivery and fetal outcomes， compared with the patients in puerperium， the patients in pregnancy had a significantly higher proportion of patients with early termination of pregnancy （50.00% vs 0，χ²=20.528， P<0.001） and a significantly lower proportion of patients with cesarean section （36.36% vs 76.92%， χ²=4.756， P=0.029）. There were no significant differences in the incidence rates of adverse events such as abnormal fetal development and stillbirth between the two groups （P>0.05）. ConclusionWith strict control of ERCP indications and timing， ERCP is effective and relatively safe in both pregnancy and puerperium and has a comparable incidence rate of post-ERCP complications to that in the general population， with relatively good delivery and fetal outcomes.