OBJECTIVE: To compare conservative management and appendectomy for acute appendicitis during pregnancy by trimester. METHODS: This retrospective cohort study used data from a national inpatient database from July 2010 to March 2022. Pregnant women diagnosed with acute appendicitis were included. Multivariable analysis using generalized estimating equations was performed to compare outcomes between conservative management and appendectomy across trimesters. The main outcomes were preterm labor, preterm delivery, or abortion
antepartum hemorrhage
duration of hospitalization
and duration of antibiotic use. RESULTS: A total of 3158 individuals from 632 acute-care hospitals were eligible. The proportion of conservative management versus appendectomy by trimester were 507 (49.1%) versus 525 (50.9%) in the first, 690 (44.6%) versus 856 (55.4%) in the second, and 337 (58.1%) versus 243 (41.9%) in the third. In the second trimester, appendectomy was associated with a higher rate of preterm delivery, preterm labor, or abortion (odds ratio [OR], 2.91 [95% confidence interval (CI), 1.62-5.25]). Antepartum hemorrhage occurred more frequently for appendectomy in the first (OR, 2.12 [95% CI, 1.31-3.43]) and third (OR, 2.43 [95% CI, 1.79-3.31]) trimesters. Appendectomy was associated with a longer duration of hospitalization in the second (2.15 days
95% CI, 1.14-3.17 days) and third (3.97 days
95% CI, 2.22-5.71 days) trimesters. Antibiotic use duration was shorter for appendectomy in the first (-1.20 days [95% CI -1.51 to -0.90 days]) and second (-0.61 days [95% CI -0.90 to -0.32 days]) trimesters. CONCLUSIONS: Clinical outcomes of acute appendicitis during pregnancy vary by trimester. Considering the appendectomy risks, conservative management may be viable depending on the clinical context and trimester.