Shoulder dystocia is defined as a vaginal cephalic delivery that requires additional obstetric manoeuvres to deliver the fetus after the head has delivered and gentle traction has failed. Shoulder dystocia occurs when either the anterior, or less commonly the posterior, fetal shoulder impacts on the maternal symphysis, or sacral promontory, respectively. There is a wide variation in the reported incidence of shoulder dystocia. Studies involving the largest number of vaginal deliveries (34 800 to 267 228) report incidences between 0.58% and 0.70%. There can be significant perinatal morbidity and mortality associated with the condition, even when it is managed appropriately. Maternal morbidity is increased, particularly the incidence of postpartum haemorrhage (11%) as well as third and fourth-degree perineal tears (3.8%). Their incidences remain unchanged by the number or type of manoeuvres required to effect delivery. Brachial plexus injury (BPI) is one of the most important fetal complications of shoulder dystocia, complicating 2.3% to 16% of such deliveries. Most cases of BPI resolve without permanent disability, with fewer than 10% resulting in permanent neurological dysfunction. In the UK and Ireland, the incidence of BPI was 0.43 per 1000 live births. However, this may be an underestimate as the data were collected by paediatricians, and some babies with early resolution of their BPI might have been missed. There is evidence to suggest that where shoulder dystocia occurs, larger infants are more likely to suffer a permanent BPI after shoulder dystocia.
A retrospective review of all BPIs in one American hospital reported an incidence of 1 in 1000 births, with a permanent injury rate of 0.1 per 1000. Another review of 33 international studies reported an incidence of BPI of 1.4 in 1000 births, with a permanent injury rate of 0.2 per 1000 births. Neonatal BPI is the most common cause for litigation related to shoulder dystocia and the third most litigated obstetric-related complication in the UK. The NHSLA (NHS Litigation Authority) has reported that 46% of the injuries were associated with substandard care. However, they also emphasised that not all injuries are due to excess traction by healthcare professionals, and there is a significant body of evidence suggesting that maternal propulsive force may contribute to some of these injuries. Moreover, a substantial minority of BPIs are not associated with clinically evident shoulder dystocia. In one series, 4% of injuries occurred after a caesarean section, and in another series 12% of babies with a BPI were born after an uncomplicated caesarean section. When BPI is discussed legally, it is important to determine whether the affected shoulder was anterior or posterior at the time of delivery, because damage to the plexus of the posterior shoulder is considered unlikely to be due to action by the healthcare professional.
The purpose of this guideline is to review the current evidence regarding the possible prediction, prevention and management of shoulder dystocia; it does not cover primary prevention of fetal macrosomia associated with gestational diabetes mellitus. The guideline provides guidance for skills training for the management of shoulder dystocia, but the practical manoeuvres are not described in detail. These can be found in the PROMPT (PRactical Obstetric Multi-Professional Training) course manual.
The full guideline can be downloaded below as a pdf: