The association of vacuum-assisted delivery and shoulder dystocia among macrosomic newborns: a retrospective study

Although shoulder dystocia (ShD) is associated with fetal macrosomia and vacuum-assisted delivery (VAD), the independent role of the latter in the occurrence of ShD is yet to be completely elucidated, as it is difficult to study its true independent contribution to ShD formation in the presence of many confounding factors. Therefore, we aimed to study whether VAD is independently associated with an increased risk for ShD among macrosomic newborns. A retrospective cohort study from a single tertiary medical center including all women who delivered vaginally a macrosomic infant during 2011–2020. We allocated the study cohort into two groups: (1) VAD (2) spontaneous vaginal deliverys, and analyzed risk factors for ShD. A multivariate regression analysis was performed to identify determinants independently associated with ShD occurrence. Of 2,664 deliveries who met the study inclusion criteria, 118 (4.4%) were VAD. The rate of ShD in the entire cohort was 108/2664 (4.1%). The following factors were more frequent among the VAD group: no previous vaginal delivery [odds ratio (OR) 2.4 (95% confidence interval (CI) 1.4–4.0, p