Poster Presentation - SOMANZ ASM Society of Obstetric Medicine of Australia and New Zealand ASM 2023

The P4 Study: Post-partum Body Composition in Normotensive vs Hypertensive Pregnancies (#74)

Jennifer J Yang 1 2 , Megan L Gow 2 3 4 , Lynne Roberts 1 2 , Gregory K Davis 1 2 , Tony J O'Sullivan 5 6 , Amanda Henry 1 2 5 7
  1. Discipline of Women's Health, UNSW Medicine and Health, Sydney, NSW, Australia
  2. Women’s and Children’s Health, St George Hospital, Kogarah, NSW, Australia
  3. Westmead Children's Hospital Clinical School, The University of Sydney, Sydney, NSW, Australia
  4. Discipline of Paediatrics and Child Health, UNSW Medicine and Health, Sydney, NSW, Australia
  5. St George and Sutherland Clinical Campus, UNSW Medicine and Health, Sydney, NSW, Australia
  6. Department of Endocrinology, St George Hospital, Kogarah, NSW, Australia
  7. The George Institute, Sydney, NSW, Australia

Introduction

Gestational weight gain is expected due to physiologic body composition changes during pregnancy. Women experience 1-3kg of postpartum weight retention on average. Increased weight retention is a risk factor for long-term obesity, diabetes and associated cardiometabolic diseases. This risk is greater in women who experienced a hypertensive disorder of pregnancy, possibly mediated by postpartum body composition changes, however normative postpartum body composition data for comparison is not available in the literature. The aims of this study were to: (1) establish a reference range for body composition in normotensive women at 6-months postpartum, including for Caucasian versus Asian populations (2) compare body composition 6-months postpartum between women who had normotensive pregnancies (NP), gestational hypertension (GH) and preeclampsia (PE), and (3) assess major determinants of postpartum body composition.

 

Methods

This study represents cross-sectional analyses at 6-months postpartum from the Postpartum, Physiology, Psychology and Paediatrics (P4) prospective cohort study. English-speaking women with live singleton births were included. Demographic data were collected from medical records, and women completed a survey including details of their health and their baby. Body composition was determined via bio-impedance analysis, using a multi-frequency body composition monitor (Fresenius Medical Care, Australia). The study population was split into NP, GH and PE groups. Amongst NP, the body composition of two sub-populations were studied: Caucasian women and Asian women. Multiple linear regression was performed to examine predictors of body fat percentage (BF%).

 

Results

388 women were included: 280 NP, 21 GH, 87 PE. 95% reference range for body fat percentage (BF%) was 17-54% amongst all NP, and 18-54% for Caucasian versus 14-51% for Asian women (p = 0.02). Average postpartum BF% was highest after GH (44 ± 7%), followed by PE (39 ± 9%) and lowest in NP (36 ± 9%) [p < 0.001 between groups]. Weight, fat mass and adipose tissue mass were also higher in GH/PE groups, whilst lean tissue mass and fat free mass were lower than NP. Significant predictors of post-partum BF% in multiple linear regression were GH/PE, Caucasian ethnicity, gestational diabetes mellitus, higher antenatal Edinburgh depression score, and cessation of breastfeeding by 6 months, explaining 13% of total proportion of variance in BF%.

 

Conclusion

A postpartum body composition reference range for NP, which differs between Caucasian and Asian women, was established. Experiencing GH/PE was independently associated with significantly increased postpartum BF%, which may contribute to known longer-term obesity and cardiometabolic risk.