Poster Presentation Australian and New Zealand Obesity Society Annual Scientific Conference 2024

Why do findings between rigorous randomised trials and meta-analyses evaluating pregnancy interventions to limit gestational weight gain differ? (#218)

Jodie M Dodd 1 2 , Andrea R Deussen 1 , Amanda J Poprzeczny 1 2 , Laura J Slade 1 2 , Megan Mitchell 1 , Jennie Louise 3 4
  1. Robinson Research Institute, University of Adelaide, Adelaide, South Australia, Australia
  2. Department of Obstetrics and Gynaecology, Women’s and Babies Division, The Women’s and Children’s Hospital, Adelaide, South Australia, Australia
  3. SAHMRI Women and Kids, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
  4. Women’s and Children’s Research Centre, Women’s and Children’s Hospital Research Network, Adelaide, South Australia, Australia

Objective

Randomised controlled trials of diet and physical activity (PA) interventions in pregnancy consistently demonstrate little impact on gestational weight gain (GWG) and pregnancy outcomes (1, 2), although meta-analyses report some benefit (3, 4). Our aim was to evaluate how the quality of included trials impacted treatment effect estimates.

Study design

We conducted a systematic review of dietary and/or PA interventions for pregnant women with a body mass index >18.5kg/m2. Studies were assessed for risk of bias and methodological features impacting reliability. Trials were classified based on the level of potential bias (no/negligible, minimal, moderate or substantial risk of bias) and intervention type (diet and/or PA). Outcomes included GWG; gestational diabetes mellitus (GDM); pre-eclampsia; caesarean birth; and birth weight measures. A sequence of meta-analyses were performed for each outcome, based on intervention type and level of potential bias in the effect estimate.

Results

We identified 128 eligible studies. The most robust estimate from a combined diet and PA behavioural intervention, with only studies at negligible risk of bias, was a difference in GWG of 1.10kg (95% CI -1.62 to -0.58; 17,755 women). There was no evidence of an effect on any clinical outcomes.

Conclusions

These findings highlight discrepancies produced by the indiscriminate inclusion of studies with methodological flaws in previous systematic reviews. A continued focus on GWG as an outcome and advocating for the implementation of antenatal dietary and PA interventions is ineffective, and may be harmful, in the absence of beneficial clinical outcomes. Our findings do not support the regular weighing of pregnant women, a practice which may distract from the consideration of other strategies to improve maternal health.

  1. Dodd JM, Turnbull D, McPhee AJ, Deussen AR, Grivell RM, Yelland LN, et al. Antenatal lifestyle advice for women who are overweight or obese: LIMIT randomised trial. BMJ. 2014;348: g1285.
  2. Poston L, Bell R, Croker H, Flynn AC, Godfrey KM, Goff L, et al. Effect of a behavioural intervention in obese pregnant women (the UPBEAT study): a multicentre, randomised controlled trial. Lancet Diabetes Endocrinol. 2015;3:767–77.
  3. Teede HJ, Bailey C, Moran LJ, Bahri Khomami M, Enticott J, Ranasinha S, et al. Association of antenatal diet and physical activity-based interventions with gestational weight gain and pregnancy outcomes: a systematic review and meta-analysis. JAMA Intern Med. 2022;182:106–14.
  4. Cantor AG, Jungbauer RM, McDonagh M, Blazina I, Marshall NE, Weeks C, Fu R, Leblanc ES, Chou R. Counseling and behavioral interventions for healthy weight and weight gain in pregnancy: evidence report and systematic review for the US Preventive Services Task Force. Jama. 2021 May 25;325(20):2094-109.