Introduction: Gestational diabetes mellitus (GDM) is the leading complication during pregnancy, with a higher incidence in women with obesity. Bariatric surgery is currently one of the most successful methods of weight loss, increasingly common in reproductive-aged women (1). Bariatric surgery has been shown to reduce the risk of developing GDM (2), however the ramifications of prior surgery and GDM-related effects remains unclear. This study aims to investigate the influence of GDM on pregnancy outcomes in women who have undergone bariatric surgery.
Method: Using NSW linked perinatal, hospital and mortality population data (2016-2020), this retrospective cohort study included women who underwent bariatric surgery and subsequently became pregnant. We divided the cohort into women who developed GDM (543) and those who did not (2,574). Multivariate logistic regression was performed to analyse a comprehensive range of perinatal outcomes.
Results: GDM was associated with a higher likelihood of large-for-gestational age infants (aOR=1.76, 95%CI: 1.32, 2.02, p<0.001), preeclampsia (aOR=1.66, 95%CI: 1.05, 2.63, p=0.029), neonatal resuscitation (aOR=1.34, 95%CI: 1.02, 1.73, p=0.033), neonatal hypoglycaemia (aOR=5.67, 95%CI: 4.27, 7.53, p<0.001), preterm delivery (aOR=1.67, 95%CI: 1.19, 2.34, p=0.003) and a composite score of neonatal adverse outcomes (aOR 2.10, 95%CI: 1.20, 2.05, p=0.009). No significant association was found between GDM and small-for-gestational age, postpartum haemorrhage, instrumental delivery, caesarean section, birth injury, APGAR scores, stillbirth, or neonatal intensive care admission.
Conclusion: These findings underscore the importance of diagnosis, and vigilant management of GDM in pregnant women with a history of bariatric surgery, especially considering the challenges faced with performing a 75g oral glucose tolerance test, often poorly tolerated in this group of women. Healthcare professionals should be attuned to the increased risks of adverse pregnancy outcomes associated with GDM in this population. Further research is warranted to develop tailored interventions that optimise maternal and neonatal outcomes in this unique cohort.