Ethnic Differences Influence the Risk of Adverse Perinatal Outcomes in Pregnant Women with Obesity
Olivia G Taylor, Tessa L Weir, Sarah J Glastras
Background
Obesity in pregnancy presents significant health risks for both the 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. 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). Perinatal outcomes were examined by logistic regression, including GDM, hypertensive diseases, LGA, and small for gestational age (SGA).
Results
Using the WHO BMI cutoffs, there were 9% of mothers with obesity compared to 11% with obesity using ethnicity-specific cutoffs (e.g., South Asians increased from 9% to 17%, respectively). Regardless of BMI cut-offs, Asian women with obesity had higher rates of GDM, hypertensive disorders, and caesarean sections, compared to Caucasian women with obesity. Asian women had lower LGA rates and higher SGA rates compared to Caucasians (e.g., by ethnicity-specific BMI cut-offs, South Asians vs. Caucasians for LGA 12% vs 30%, OR 0.35, CI 0.28-0.44, and SGA 8% vs 3%, OR 2.97, CI 2.04-4.32). In this cohort, the presence of GDM in the pregnancy did not increase the rates of LGA.
Conclusions
These findings suggest that BMI and ethnicity influence both maternal and neonate adverse outcomes. Notably, while there are some differences in specific values between the BMI cut-offs, the overall trends in maternal and neonate outcomes remained consistent. The study demonstrates the need for personalised care with nuanced classifications to improve maternal and neonate health.
References
- 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.