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

Comparison of Adverse Perinatal Outcomes between Asian and Caucasian Women with Obesity (98335)

Olivia G Taylor 1 , Joshua G Lee 2 , Tessa L Weir 3 4 5 6 , Sarah J Glastras 3 4 6
  1. School of Medicine, The University of Notre Dame, Darlinghurst, NSW, Australia
  2. School of Medicine, The University of Sydney, Camperdown, NSW, Australia
  3. Department of Diabetes, Endocrinology & Metabolism, Royal North Shore Hospital, St Leonards, NSW, Australia
  4. Kolling Institute, St Leonards, NSW, Australia
  5. Department of Endocrinology, Nepean-Blue Mountains Hospital, Sydney, NSW, Australia
  6. Faculty of Medicine and Health, The University of Sydney, Royal North Shore Hospital, St Leonards, NSW, Australia

Background  
Obesity in pregnancy presents significant health risks for both mother and child, with increased rates of gestational diabetes mellitus (GDM), preeclampsia, caesarean section, and large-for-gestational-age (LGA)1. The current WHO classification of obesity2 does not adequately account for ethnic differences, potentially overlooking ethnicity-specific, obesity-related perinatal risks. Australia is culturally and ethnically diverse. Few studies have focused on the impact of maternal obesity and ethnicity on maternal and neonate outcomes in Australia. This study aimed to explore how ethnicity impacts perinatal outcomes in mothers with obesity.  

Methods 
This retrospective cohort study involved pregnancy data from the Northern Sydney Local Health District, Sydney, Australia (2012-2022). Women were categorised into ethnicity based on country of birth; Caucasian, East Asian, South Asian, and South-East Asian and they were categorised by either WHO obesity cutoffs (≥30 kg/m2) or ethnicity-specific cutoffs (Caucasian ≥30kg/m2, all Asians ≥27.5 kg/m2)3. Perinatal outcomes were examined by Chi-squared testing and logistic regression, including mode of delivery, GDM, LGA, small for gestational age (SGA), and hypoglycemia.

Results  

Using WHO BMI cutoffs, 9% of mothers had obesity, compared to 11% of mothers with obesity using ethnicity-specific cutoffs (e.g., South Asians increased from 8% to 18%, respectively). Regardless of BMI cutoffs, Asian women with obesity had higher rates of GDM, instrumental delivery and caesarean sections, compared to Caucasian women with obesity. There was a consistent relationship between ethnicity and LGA/SGA regardless of BMI cutoffs, however with ethnicity-specific BMI cutoffs, Asians had lower LGA rates and higher SGA rates compared to Caucasians (e.g., South Asian LGA 12% vs 30%, OR 0.36, CI 0.28-0.45, and SGA 8% vs 3%, OR 2.91, CI 2.02-4.18). South Asians had higher rates of neonate hypoglycemia compared to Caucasians (OR 1.75, CI 1.34- 2.27, p <0.001), whereas East Asians had lower rates of neonate respiratory distress and NICU admission (OR 0.63, CI 0.41- 0.98, p = 0.04 and OR 0.58, CI 0.38-0.88, p = 0.01, respectively).

Conclusions  
This study reveals distinct variations in outcomes among different ethnic groups for maternal and neonate adverse outcomes in maternal obesity. These findings show that using ethnicity-specific cutoffs facilitates more accurate LGA and SGA incidence rate determination for Asian women, with reduced LGA but increased SGA rates by 3-fold compared to Caucasians. The findings emphasize the urgency of understanding ethnic-specific health risks and sociocultural determinants to enhance personalised care, and early interventions and improve maternal and neonate well-being.

  1. Akinyemi OA, Tanna R, Adetokunbo S, et al. Increasing Pre-pregnancy Body Mass Index and Pregnancy Outcomes in the United States. Cureus 2022; 14: e28695. 20220902. DOI: 10.7759/cureus.28695.
  2. World Health Organisation. Obesity and overweight, https://www.who.int/news-room/fact-sheets/detail/obesity-and-overweight (2021, accessed 03/06/23 2023).
  3. WHO Expert Consultation. Appropriate body-mass index for Asian populations and its implications for policy and intervention strategies. Lancet. 2004 Jan 10;363(9403):157-63. doi: 10.1016/S0140-6736(03)15268-3. Erratum in: Lancet. 2004 Mar 13;363(9412):902. PMID: 14726171.