Axillary Traction: An Effective Method of Resolving Shoulder Dystocia

Ansell, Lesley
McAra-Couper, Judith
Larmer, Peter
Garrett, Nicholas
Item type
Degree name
Doctor of Health Science
Journal Title
Journal ISSN
Volume Title
Auckland University of Technology

Shoulder dystocia is a childbirth emergency which can result in significant neonatal morbidity and in some cases perinatal death. It is crucial therefore that management of shoulder dystocia is timely and efficient to reduce the risks of perinatal injury, some of which are permanent, or perinatal death.

Widely accepted manoeuvres for resolving shoulder dystocia include a series of external and internal manoeuvres (internal rotational manoeuvres known as Rubins’ or Woods’ screw) and delivery of the posterior arm. It is generally accepted that the more severe dystocias will require an internal manoeuvre for resolution and it is management by internal manoeuvres that is the focus of this study.

The main objective of this research is to evaluate the success rates of axillary traction which is an alternative internal manoeuvre for resolution of shoulder dystocia. This manoeuvre was introduced into clinical practice in Counties Manukau Health (CMH) in 2009 following qualitative research on the topic (Ansell et al., 2012). Counties Manukau Health is the largest District Health Board (DHB) in New Zealand and was the first to implement the use of axillary traction in an ethnically diverse population with high health needs including diabetes, obesity and fetal macrosomia. This is the first study to provide quantitative analysis of the success rates of axillary traction for the resolution of shoulder dystocia.

This thesis presents a systematic review of the literature examining the success rates of internal rotational manoeuvres and delivery of the posterior arm alongside complications associated with those manoeuvres. The review highlighted the conflicting definitions and diagnosis given for shoulder dystocia which makes evaluation of success rates and neonatal outcomes for individual manoeuvres difficult. The success rates given were wide ranging from 9.4% for internal rotation (Spain et al., 2015) to 100% for internal manoeuvres described as fetal manipulation (Gachon et al., 2016). The overall brachial plexus injury (BPI) rate was significantly higher with internal rotation (p<0.001) than delivery of the posterior arm (Michelotti et al., 2018). Posterior arm delivery was found to be more successful than internal rotation (Hoffman et al, 2011) but humeral fractures were higher with this manoeuvre (Leung et al., 2011; Michelotti et al., 2018). The more manoeuvres used to resolve the dystocia and the longer the head to body delivery interval (HBDI), the worse the neonatal outcomes (p<0.01) (Gherman et al., 1997, Spain et al., 2015; Michelotti et al., 2018). This review a highlighted the need for an effective method of managing shoulder dystocia in a timely manner.

A quantitative study was undertaken to assess the effectiveness of the alternative internal manoeuvre of axillary traction for resolution of shoulder dystocia (Ansell et al., 2019). The study population were women with a singleton fetus, cephalic presentation and beyond 34 weeks gestation who had experienced shoulder dystocia. Records over an eight-year period were reviewed (2006-13) and 226 women required an internal manoeuvre for resolution of shoulder dystocia. Data were analysed using the Statistical Package for the Social Sciences (SPSS) version 24 (IBM, Armonk, NY, USA). Demographic and clinical data for the three internal manoeuvre cohorts were compared. Categorical data were compared using Chi-Square and Fisher's exact tests. Continuous data were compared using Student's t test (normal distribution) or Mann–Whitney or Kruskall–Wallace test for non-normal distributions. Where differences between the cohorts were noted with categorical data, the success rates of the internal manoeuvres were compared using Chi-Square or Fisher's exact test.

There were three main groups of internal manoeuvres used:

  1. axillary traction which included all manoeuvres documented as axillary traction or removal of the posterior shoulder;
  2. posterior arm delivery which was documented as such; and
  3. internal rotational manoeuvres which included all manoeuvres documented as Woods' screw, reverse Woods' screw and/or internal rotation.

The results of that study showed that axillary traction had a significantly higher success rate of 95.8% (p<0.001) when used as the first internal manoeuvre versus posterior arm (85.7%) and internal rotation (48.3%). There was no significant difference in the maternal and neonatal complication rates between the cohorts. The Ansell et al. (2019) study demonstrates that axillary traction is an effective manoeuvre for the resolution of shoulder dystocia and can be used in all women regardless of co-morbidities.

The final part of this research study is a qualitative narrative which demonstrates how the process of reflection and critical analysis identified a gap in the available evidence for management of shoulder dystocia. This led to clinical dialogue and a realisation that many other practitioners had similar experiences. Following ongoing investigation, research and peer review, the process of clinical leadership resulted in a change in clinical practice. The willingness of other practitioners to accept and learn the manoeuvre of axillary traction demonstrates how ‘research in action’ has effected a change in how to manage shoulder dystocia.

In conclusion, axillary traction has a significantly higher success rate than other internal manoeuvres (p<0.001) without any increase in maternal or neonatal morbidity. It can be used for any woman in any circumstance and it is recommended that this be the first internal manoeuvre attempted when shoulder dystocia occurs.

Shoulder dystocia , Axillary traction , Rotational manoeuvres , Posterior arm delivery
Publisher's version
Rights statement