Avoiding over diagnosis of shoulder dystocia

Abstract

In this study, we aimed to distinguish true shoulder dystocia from mere difficulty with delivery of the shoulder, by investigating the risk factors that lead to shoulder dystocia. Shoulder dystocia is a bony problem which occurs when either the anterior or, less commonly, the posterior fetal shoulder impacts on the maternal symphysis pubis or sacral promontory. Failure to apply the Royal College of Obstetricians and Gynaecologists (RCOG) clinical diagnostic criteria for shoulder dystocia has made it susceptible to over-diagnosis due to inclusion of all difficult shoulder deliveries, including those related to an inappropriate maternal position. This was a retrospective analysis of risk factors associated with 56 cases of shoulder dystocia which occurred in West Middlesex University Hospital between 2003 and 2004. The cases were analysed in two categories, good outcome and poor outcome, and compared with each other. The poor outcome had represented true shoulder dystocia. The incidence of shoulder dystocia increased from 0.94% in 2003 to 1.37% in 2004. However, the incidence of those with a poor outcome decreased from 45.4% of the whole shoulder dystocia group in 2003, to 17.6% in 2004 (p = 0.03). There were no clear diagnostic criteria documented in the notes for the condition other than the birth attendants' opinion and the turtle sign. This may either reflect over-diagnosis from increased awareness or possibly improvement in the outcome due to training and education. Interestingly, at least four risk factors were identified in each of the cases with poor outcome. A registrar conducting the delivery, forceps delivery for delayed second stage and the turtle sign were significantly common findings among the true shoulder dystocia group. Multiple risk factors can be a good predictor for the occurrence of shoulder dystocia. Applying the RCOG diagnostic criteria for shoulder dystocia may lead to improvement in diagnosis and therefore a better understanding of the risk factors and future management of shoulder dystocia.