INTRODUCTION: To compare delivery outcomes in pregnant women with a body mass index (BMI) ≥40based on the planned and actual mode of delivery. METHODS: Five databases were searched until July 2017 to identify studies that reported on delivery outcomes in women with BMI ≥40. Outcomes were presented as proportions. Relative risks (RR) and 95% confidence intervals were calculated using random-effects meta-analysis. RESULTS: Eight observational studies with low risk-of-bias (Newcastle-Ottawa Scale) were included. Based on 1597 pregnancies, planned vaginal birth (VB) vs. planned caesarean delivery (CD) was associated with higher risk for postpartum hemorrhage (PPH) [7.27% vs. 3.44%, RR 2.116 (1.02-4.40)] and low five-minute Apgars [4.51% vs. 1.53%, RR 2.955 (1.01-8.63)]. Based on 4144 pregnancies, planned trial of scar after caesarean vs. repeat CD was associated with higher risk for endometritis [4.97% vs. 2.19%, RR 2.22 (1.60-3.09)], low five-minute Apgars [4.94% vs. 1.68%, RR 2.98 (2.03, 4.28)], birth trauma [1.06% vs. 0.21% RR 4.61 (1.77-12.03)] and prolonged hospitalization [30.3% vs. 26% RR 1.163 (1.05-1.29)]. Based on 3625 pregnancies, successful VB vs. intrapartum CD was associated with lower risk of PPH [15.06% vs 69.96%, RR 0.21 (0.19-0.23)], wound disruption [0% vs. 4.44%, RR 0.05 (0.003-0.88)], prolonged hospitalization [1.9% vs. 6.67%, RR 0.28 (0.08-0.98)] and low five-minute Apgars (0.95% vs. 5.56%, RR 0.17 (0.03-0.86)], but more birth trauma [5.91% vs. 0.56% RR 6.56 (1.26-34.10)]. Compared groups had dissimilar demographic characteristics. CONCLUSION: Given the clinical equipoise, a randomized trial is needed to determine the optimal mode of delivery in women with BMI ≥40.