Healthy weight gain during pregnancy

Gaining weight during pregnancy is normal and expected. Keeping within recommended weight gain ranges during pregnancy is associated with better health for both women and their children.1 So what is healthy and why is weight gain needed during pregnancy?

Gestational weight gain is the total amount of weight gained by a person during pregnancy. Weight gain is expected and encouraged during pregnancy in order to have safe and healthy outcomes for both mother and baby.

Additional weight gain is needed to support biological changes that occur during pregnancy.2 This extra weight is made up of several different factors such as:

  • Weight of the developing baby
  • Placental weight
  • Amniotic fluid within the womb
  • Increase in volume of blood in the body
  • Increase in breast tissue.

The amount of weight gain that is recommended during pregnancy varies depending on a person’s current weight status and body mass index (BMI, kg/m2). Recommendations are based on reducing risks for both mother and baby. There are known risks with gaining too little weight and with gaining too much weight. Gaining less weight than recommended can increase the risk of giving birth prematurely and increase the baby’s likelihood of being underweight. Gaining more weight than recommended can increase the risk of pregnancy complications like gestational diabetes and pre-eclampsia, along with delivery complications.1

What does healthy weight gain during pregnancy look like?

Gestational weight gain depends on multiple factors such as a woman’s weight prior to pregnancy and if the pregnancy is a singleton or multiple pregnancy (such as twins, triplets etc). Guidelines for appropriate weight gain have made by the Institute of Medicine3 which bases recommendations on a person’s pre-pregnancy BMI category:

  • Underweight (BMI <18.5 kg/m2): 12.5-18 kg weight gain.
  • Normal weight (BMI 18.5-24.9 kg/m2): 11.5-16 kg weight gain.
  • Overweight (BMI 25-29.9 kg/m2): 7-11.5 kg weight gain.
  • Obesity (BMI of > 30 kg/m2): 5-9 kg weight gain.

These weight gain recommendations are based on improving health outcomes for both mother and child and were most consistently associated with good outcomes.3 This is particularly important in terms of managing both current and future health risks for both mother and baby.

Most weight gain that occurs during pregnancy should occur during the second and third trimester. There are resources available, such as gestational weight gain calculators. based on these recommendations which help calculate what weight gain should look like through the different stages of pregnancy. One such gestational weight gain calculator was developed by Medibank, alongside our Monash Research Team.

How is this important for future health?

Exceeding the healthy weight gain recommendations during pregnancy can mean women are less likely to return to the weight they were before they were pregnant, putting them at higher risk for future pregnancies and for adverse health later in life.4  Supporting women to keep within the recommended guidelines is a priority for healthcare professionals and all stakeholders. Preventing adverse outcomes for both women and children is an investment in future health.

Lifestyle interventions during pregnancy have been shown to support optimal gestational weight gain and reduce the risk of conditions such as gestational diabetes and obesity.5,6,7  Furthermore, we know what types of interventions work best to support women around weight management, with research highlighting the value of interventions with components that target diet, physical activity, and include behaviour change techniques.8,9 The Bump2Baby and Me intervention integrates best practice evidence from previous research that successfully reduced excess weight gain during pregnancy and supported women postpartum.10,11,12 This information was combined to design an evidence-based system of care delivered via a smartphone application for accessibility.

A challenge that remains is that trial interventions often do not move beyond the research phase to consider how this could work in the real world or be implemented into existing routine health services. The Bump2Baby and Me project is addressing this by evaluating the real-world implementation of this trial at clinical sites in Europe (Ireland, Spain, United Kingdom) and Australia. The project will evaluate the effectiveness of the intervention on gestational weight gain and postpartum weight retention, while also evaluating the fit of the intervention into routine antenatal and postnatal care and cost-effectiveness of the study. The project aims to produce an evidence-based, effective system of care for prevention of diabetes, overweight, and obesity when delivered ‘at scale’ across antenatal settings.


1Goldstein et al. Association of gestational weight gain with maternal and infant outcomes: a systematic review and meta-analysis.  JAMA. 2017;317(21):2207-2225. doi:10.1001/jama.2017.3635

2Institute of Medicine (US) and National Research Council (US) Committee to Reexamine IOM Pregnancy Weight Guidelines; Rasmussen KM, Yaktine AL, editors. Weight Gain During Pregnancy: Reexamining the Guidelines. Washington (DC): National Academies Press (US); 2009. 3, Composition and Components of Gestational Weight Gain: Physiology and Metabolism. Available from:

3Weight gain during pregnancy: reexamining the guidelines. Washington, DC: National Academies Press; 2009. Institute of Medicine/National Research Council (Committee to Reexamine IOM Pregnancy Weight Guidelines, Food and Nutrition Board and Board on Children, Youth, and Families). Available from:

4Nehring et al. Gestational weight gain and long-term postpartum weight retention: a meta-analysis.  Am J Clin Nutr. 2011;94(5):1225-1231. doi:10.3945/ajcn.111.015289

5Farpour-Lambert NJ, Ells LJ, Martinez de Tejada B, Scott C. Obesity and weight gain in pregnancy and postpartum: an evidence review of lifestyle interventions to inform maternal and child health policies. Front. Endocrinol.(2018) 9:546. doi: 10.3389/fendo.2018.00546

6The International Weight Management in Pregnancy (i-WIP) Collaborative Group. Effect of diet and physical activity based interventions in pregnancy on gestational weight gain and pregnancy outcomes: meta-analysis of individual participant data from randomised trials. BMJ. (2017). 358:j3119. doi: 10.1136/bmj.j3119

7 Bennett CJ, Walker RE, Blumfield ML, Gwini S-M, Ma J, Wang F, et al. Interventions designed to reduce excessive gestational weight gain can reduce the incidence of gestational diabetes mellitus: a systematic review and meta-analysis of randomised controlled trials. Diabetes Research and Clinical Practice. 2018;141:69–79.

8Teede 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 Feb 01;182(2):106-114. doi: 10.1001/jamainternmed.2021.6373

9Lim S, Liang X, Hill B, Teede H, Moran LJ, O’Reilly S. A systematic review and meta-analysis of intervention characteristics in postpartum weight management using the TIDieR framework: a summary of evidence to inform implementation. Obes Rev. 2019;20(7):1045–56.

10Kennelly MA, Ainscough K, Lindsay KL, O’Sullivan E, Gibney ER, McCarthy M, et al. Pregnancy exercise and nutrition with smartphone application support: a randomized controlled trial. Obstet Gynecol. 2018;131(5):818–26.

11O’Reilly SL, Dunbar JA, Versace V, Janus E, Best JD, Carter R, et al. Mothers after Gestational Diabetes in Australia (MAGDA): a randomised controlled trial of a postnatal diabetes prevention program. PLOS Med. 2016;13(7): e1002092.

12Russell CG, Denney-Wilson E, Laws RA, Abbott G, Zheng M, Lymer SJ, et al. Impact of the growing healthy mHealth program on maternal feeding practices, infant food preferences, and satiety responsiveness: quasiexperimental study. JMIR Mhealth Uhealth. 2018;6(4):e77. doi: 10.2196/mhealth.9303