[Macrosomia, shoulder dystocia and elongation of the brachial plexus: what is the role of caesarean section?]

Overview of techniques to manage shoulder dystocia during vaginal birth

Shoulder dystocia is an obstetric emergency which is unpredictable and complicates approximately 0.5-1% of vaginal births. This article discusses the risk factors and the associated fetal and maternal complications, while it is also an overview of techniques and algorithms to handle shoulder dystocia.

Influence of Foetal Macrosomia on the Neonatal and Maternal Birth Outcome

Introduction Foetal macrosomia is associated with various obstetrical complications and is a common reason for inductions and primary or secondary Caesarean sections. The objective of this study is the generation of descriptive data on the mode of delivery and on maternal and foetal complications in the case of foetal macrosomia. The causes and consequences of foetal macrosomia as well as the rate of shoulder dystocia are examined in relation to the severity of the macrosomia.

Patients The study investigated all singleton births ≥ 37 + 0 weeks of pregnancy with a birth weight ≥ 4000 g at the Charité University Medicine Berlin (Campus Mitte 2001 – 2017, Campus Virchow Klinikum 2014 – 2017).

Results 2277 consecutive newborns (birth weight 4000 – 4499 g [88%], 4500 – 4999 g [11%], ≥ 5000 g [1%]) were included. Maternal obesity and gestational diabetes were more common in the case of newborns weighing ≥ 4500 g than newborns weighing 4000 – 4499 g (p = 0.001 and p < 0.001). Women with newborns ≥ 5000 g were more often ≥ 40 years of age (p = 0.020) and multipara (p = 0.025). The mode of delivery was spontaneous in 60% of cases, vaginal-surgical in 9%, per primary section in 14% and per secondary section in 17%. With a birth weight ≥ 4500 g, a vaginal delivery was more rare (p < 0.001) and the rate of secondary sections was increased (p = 0.011). Women with newborns ≥ 4500 g suffered increased blood loss more frequently (p = 0.029). There was no significant difference with regard to the rate of episiotomies or serious birth injuries. Shoulder dystocia occurred more frequently at a birth weight of ≥ 4500 g (5 vs. 0.9%, p = 0.000). Perinatal acidosis occurred in 2% of newborns without significant differences between the groups. Newborns ≥ 4500 g were transferred to neonatology more frequently (p < 0.001).

Conclusion An increased birth weight is associated with an increased maternal risk and an increased rate of primary and secondary sections as well as shoulder dystocia; no differences in the perinatal outcome between newborns with a birth weight of 4000 – 4499 g and ≥ 4500 g were seen. In our collective, a comparably low incidence of shoulder dystocia was seen. In the literature, the frequency is indicated with a large range (1.9 – 10% at 4000 – 4499 g, 2.5 – 20% at 4500 – 5000 g and 10 – 20% at ≥ 5000 g). One possible cause for the low rate could be the equally low prevalence of gestational diabetes in our collective. A risk stratification of the pregnant women (e.g. avoidance of vacuum extraction, taking gestational diabetes into account during delivery planning) is crucial. If macrosomia is presumed, it is recommended that delivery take place at a perinatal centre in the presence of a specialist physician, due to the increased incidence of foetal and maternal complications.