BackgroundCaesarean section (CS) is widely perceived as protective against obstetric brachial plexus injury (BPI), but few studies acknowledge the factors associated with such injury. The objectives of this study were therefore to aggregate cases of BPI after CS, and to illuminate risk factors for BPI.MethodsPubmed Central, EMBASE and MEDLINE databases were searched using free text: (“brachial plexus injury” or “brachial plexus injuries” or “brachial plexus palsy” or “brachial plexus palsies” or “Erb’s palsy” or “Erb’s palsies” or “brachial plexus birth injury” or “brachial plexus birth palsy”) and (“caesarean” or “cesarean” or “Zavanelli” or “cesarian” or “caesarian” or “shoulder dystocia”). Studies with clinical details of BPI after CS were included. Studies were assessed using the National Institutes for Healthy Study Quality Assessment Tool for Case Series, Cohort and Case-Control Studies.Main results39 studies were eligible. 299 infants sustained BPI after CS. 53% of cases with BPI after CS had risk factors for likely challenging handling/manipulation of the fetus prior to delivery, in the presence of considerable maternal or fetal concerns, and/or in the presence of poor access due to obesity or adhesions.ConclusionsIn the presence of factors that would predispose to a challenging delivery, it is difficult to justify that BPI could occur due to in-utero, antepartum events alone. Surgeons should exercise care when operating on women with these risk factors.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12884-023-05696-1.