Poster Presentation International Association of the Diabetes and Pregnancy Study Groups 2022 - Hosted by ADIPS

Shoulder dystocia in Australian Aboriginal babies born to mothers with diabetes (#80)

Marwan Ahmed 1 2 , Helen D Bailey 2 3 , Gavin Pereira 4 5 6 , Scott W White 7 8 , Kingsley Wong 2 4 , Rhonda Marriott 9 , Matthew J.L Hare 10 11 , Carrington CJ Shepherd 2 3 9
  1. School of Population and Global Health, The University of Western Australia, Perth, Australia
  2. The University of Western Australia (Telethon Kids Institute), Perth, WA, Australia
  3. Curtin Medical School, Faculty of Health Sciences, Curtin University, Perth, Australia
  4. Curtin School of Population Health, Curtin University, Perth, Western Australia, Australia
  5. Centre for Fertility and Health (CeFH), Norwegian Institute of Public Health, Oslo, Norway
  6. enAble Institute, Curtin University, Perth, Western Australia, Australia
  7. Division of Obstetrics and Gynaecology, The University of Western Australia, Perth, WA, Australia
  8. Maternal Fetal Medicine Service, King Edward Memorial Hospital, Subiaco, WA, Australia
  9. Ngangk Yira Research Centre, Murdoch University, Perth, WA, Australia
  10. Wellbeing and Chronic Preventable Diseases Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia
  11. Department of Endocrinology, Royal Darwin Hospital, Darwin, NT, Australia

Background

Australian Aboriginal and Torres Strait Islander (hereafter respectfully called Aboriginal) women with diabetes in pregnancy (DIP) are more likely to have glycaemic levels above the target range, and their babies are thus at higher risk of excessive fetal growth. Shoulder dystocia, defined by failure of spontaneous birth of fetal shoulder after birth of the head requiring obstetric maneuvers, is an obstetric emergency that is strongly associated with DIP and fetal size. The aim of this study was to investigate the epidemiology of shoulder dystocia in Aboriginal babies born to mothers with DIP.

Methods

This retrospective cohort study included all singleton births in Western Australia between 1998-2015, using routinely collected linked health datasets (Midwives’ Notification System and Hospital Morbidity Data Collection). Stratifying by Aboriginal status, characteristics of births complicated by shoulder dystocia in women with and without DIP were compared, and the incidence and time trends of shoulder dystocia were described. Compliance with guidelines aiming at preventing shoulder dystocia in women with DIP was compared by Aboriginal status. Post-regression estimation was used to calculate adjusted population attributable fractions (PAFs) for shoulder dystocia associated with DIP, and to estimate adjusted probabilities of shoulder dystocia in babies born to mothers with DIP at different birthweights.

Results

There were 510,761 births over the study period. Rates of shoulder dystocia in Aboriginal babies born vaginally to mothers with DIP were double that of their non-Aboriginal counterparts (6.3% vs 3.2%, p<0.001), and the disparities did not improve over time. Among mothers with DIP whose pregnancies were complicated by shoulder dystocia, Aboriginal mothers were more likely than non-Aboriginal mothers to have a history of shoulder dystocia (11.1% vs 4.0%, p=0.003). The rates of guideline-recommended caesarean section in pregnancies with diabetes and birthweight >4.5 kg were lower in Aboriginal women (28.6%) compared to non-Aboriginal women (43.1%) (p=0.004). PAFs indicated that 13.4% (95% CI: 9.7%-16.9%) of shoulder dystocia cases in the Aboriginal population (2.7% (95% CI: 2.1%-3.4%) in non-Aboriginal mothers) were attributable to DIP. Among mothers with DIP, the probabilities of shoulder dystocia among babies born to Aboriginal mothers were higher at all birthweights compared to those born to non-Aboriginal mothers.

Conclusions

Aboriginal mothers with DIP had a higher risk of shoulder dystocia and a stronger association between birthweight and shoulder dystocia. Many cases were recurrent. These factors should be considered in clinical practice and when counselling women. Barriers to appropriate access to caesarean sections should be explored.