Understanding Weight Changes in Pregnancy and Postpartum


There are two studies under this theme that focus on understanding the many personal factors that contribute to weight and body composition changes in pregnancy and postpartum (for example: dietary intake, physical activity, breastfeeding, and sedentary behaviours).

ENRICH Activities

Alberta Pregnancy Outcomes and Nutrition (APrON)-Based Studies

Numerous studies have shown the effects of what we eat on our health. However, research is limited in showing the relationship between a mother's diet during pregnancy and the long-term health outcomes of the mother and baby. APrON is a prospective cohort research study that aims to improve the short and long-term health of mothers and newborn babies in Alberta by identifying the role of nutrition in mental and neurodevelopmental disorders, and long-term neurocognitive function. Over 5000 mothers, fathers, and infants from Edmonton and Calgary participated in the APrON study between 2009 and 2013; participants entered the study from up to 24 weeks of gestation through to the third year of the infant's life, providing valuable information about their health and lifestyle.

ENRICH is using results from the APrON study to help inform the development of strategies that support women in achieving healthy weights during pregnancy and postpartum. Dr. Bell is an APrON investigator focused on maternal nutrition, weight, and health. ENRICH researchers are continuing to analyze the extensive APrON data on women's diet, physical activity patterns, weight, and body composition in pregnancy and early postpartum.  To learn more about the APrON data that ENRICH has already published, click here and here.

For more information on APrON, visit their website.   

Postpartum Calorimetry (PCAL) Study

Energy needs during the postpartum period are not well-known and what is known is from studies carried out in the 1960's and 70's. The PCAL study used a whole body calorimeter (see picture below) to precisely measure the daily energy expenditure of women at three and nine months postpartum. Fifty-two women participated, making this the largest study of its kind ever conducted.

In this study we wanted to test the accuracy of the Dietary Reference Intake (DRI) equation that is regularly used to predict women's energy requirements in the postpartum period. We tested the accuracy of this equation by comparing it with women's daily energy expenditure. Read more. 

We also wanted to explore how body composition and breastfeeding influenced postpartum weight loss. Read more here and here.
The Calorimetry Unit is a small, climate-controlled room located in the Clinical Research Unit on the second floor of the  Li Ka Shing Centre for Health Research Innovation at the University of Alberta. It is equipped with a bed, treadmill, TV, computer, chair, table, sink, and toilet, providing the comforts for daily living.

In the Media

Related Publications

  • Jarman M, Yuan Y, Pakseresht M, Shi Q, Robson PJ, Bell RC, Alberta Pregnancy Outcomes and Nutrition study team … ENRICH team . (2016). Patterns and trajectories of gestational weight gain: a prospective cohort study.. CMAJ open, 4 (2), pp. E338-45
  • Jarman MJ, Bell RCB, Nerengberg KN, Robson PR. (2017). Adherence to Canada’s Food Guide recommendations during pregnancy. Current Developments in Nutrition, 1 (6),
  • Jarman, M., Mathe, N., Ramazani, F., Pakseresht, M., Robson, P. J., Johnson, S. T., & Bell, R. C. (2018). Dietary patterns prior to pregnancy and associations with pregnancy complications.Nutrients, 10(7) doi:10.3390/nu10070914
  • Pereira, L. C. R., Elliott, S. A., McCargar, L. J., Bell, R. C., & Prado, C. M. (2018). Changes in energy metabolism from prepregnancy to postpartum: A case report. Canadian Journal of Dietetic Practice and Research, , 1-5. doi:10.3148/cjdpr-2018-016
  • Elliott, S., Pereira, L., McCargar, L., Prado, C., & Bell, R. (n.d.). Trajectory and determinants of change in lean soft tissue over the postpartum period. British Journal of Nutrition, 1-9. doi:10.1017/S0007114518002015
  • Pereira, L.C.R., Purcell, S.A, Elliott, S.A., McCargar, L.J., Bell, R.C., Robson, P.J., Prado, C.M. (2019). The use of whole body calorimetry to compare measured versus predicted energy expenditure in postpartum women. American Journal of Clinical Nutrition, 109, 554-565 doi: 10.1093/ajcn/nqy312