AbstractBackground and objectives
Severe shoulder dystocia (SD) is associated with neonatal brachial plexus injuries and skeletal fractures, with the former being the commonest cause for litigation related to birth trauma. The aim of this case-control study was to evaluate risk factors for birth injuries in cases presenting with SD.Methods
Between January 2000 and December 2006, 22 babies who sustained brachial nerve paralysis or skeletal fractures following severe SD and requiring admission to Special Care Baby Unit (SCBU) were identified. The control group (n = 22) comprised the next infant delivered who was deemed to have SD but did not suffer significant birth injuries. Antenatal, labour and postnatal data were collected and compared between the two groups.Results
The study and control groups had similar median maternal age (28 vs. 26.5 years), gestational age at delivery (40 vs. 40 weeks) and estimated blood loss (300 vs. 225 ml) (both P > 0.05, Mann-Whitney test). Median 1 min Apgar scores (5.5 vs. 7), maternal BMI (31.34 vs. 27.19 kg/m2) and duration of second stages (53.8 vs. 49.2 min) were also statistically similar in both groups (P > 0.05). However, compared to controls, brachial nerve injuries and skeletal fractures were more likely to occur in mothers with gestational diabetes (5/22 vs. 1/22) or who had previous big babies (4/22 vs. 1/22) (both P < 0.05, Fisher's exact test). Babies who had birth injuries were also more likely to have greater median birth weights (4.3 vs. 3.8 kg) and postnatal anthropometric measurements such as head circumference (35 vs. 34 cm) and ponderal indices (81.9 vs. 74.3 kg/m3) compared to controls.Conclusion
In babies with SD, brachial nerve injuries and skeletal fractures are more likely to occur in those with greater birthweights but also larger length to weight ratios. In these babies, assessment of abdominal circumference and biacromial length by magnetic resonance imaging (MRI) may help predict the likelihood of severe SD, especially in mothers with identifiable risk factors. However, further research in larger controlled trials are still needed to determine their predictive value.