Oral Presentation Australian and New Zealand Obesity Society Annual Scientific Conference 2023

Impact of Bariatric Surgery on Pregnancy Outcomes in Women with Gestational Diabetes Mellitus (98299)

Tessa Weir 1 2 , Ibinabo Ibiebele 3 , Deborah Randall 3 , Sarah Glastras 2 4
  1. Department of Endocrinology, Nepean-Blue Mountains Hospital, Sydney, NSW, Australia
  2. The University of Sydney, Northern Clinical School, Sydney, NSW, Australia
  3. Women's and Babies Research, The University of Sydney, Sydney, NSW, Australia
  4. Department of Endocrinology, Royal North Shore Hospital, St Leonards, New South Wales, Australia

Introduction: The prevalence of obesity is increasing with almost half of all pregnancies occurring in women with overweight or obesity(1). Maternal obesity is associated with adverse perinatal outcomes, including preeclampsia, preterm deliveries and increased birth weight(2). Bariatric surgery accessibility has improved, with more pregnant women having undergone this procedure. Though associated with improved fertility and lower gestational diabetes (GDM) incidence, bariatric surgery may lead to a number of adverse complications due to maternal undernutrition. While these issues are concerning in an uncomplicated pregnancy, they may pose an even greater challenge for women with a diagnosis of GDM. This study aims to evaluate the impact of bariatric surgery on pregnancy outcomes in women with GDM.

Methods: Using NSW linked perinatal, hospital and mortality population data (2016-2020), this cohort study analysed GDM pregnancies after bariatric surgery (n=543) compared to those without surgery (n=71,104). Univariate and multivariable logistic regression models were used to assess associations between bariatric surgery and a range of pregnancy outcomes.

Results: In this cohort of GDM pregnancies, bariatric surgery was associated with reduced odds of instrumental delivery and third or fourth-degree tears (OR 0.53, 95%CI: 0.37-0.75, p<0.001, OR 0.19, 95%CI: 0.05-0.76, p=0.019, respectively). Conversely, bariatric surgery increased the odds of large-for-gestational age infants and preterm delivery (OR 1.37, 95%CI: 1.11-1.70, p=0.003, OR 1.66, 95%CI: 1.27-2.17, p<0.001, respectively). After adjusting for maternal and pregnancy characteristics, only preterm delivery remained significant (aOR 1.45, 95%CI: 1.09-1.94, p=0.012).

Conclusion: A history of bariatric surgery in women with GDM confers a significant risk of preterm delivery, regardless of background maternal characteristics. These findings underscore the complexity of the relationship between bariatric surgery, GDM and pregnancy outcomes, and emphasise the importance of comprehensive risk assessment and close antenatal surveillance in GDM clinics for women who have undergone bariatric surgery.

  1. Australian Institute of Health and Welfare 2017. A picture of overweight and obesity in Australia 2017. PHE 216. Canberra: AIHW
  2. Ray JG, Vermeulen MJ, Shapiro JL, Kenshole AB. Maternal and neonatal outcomes in pregestational and gestational diabetes mellitus, and the influence of maternal obesity and weight gain: the DEPOSIT study. Diabetes Endocrine Pregnancy Outcome Study in Toronto. QJM. 2001 Jul;94(7):347-56