Most J, St Amant M, Hsia DS, et al. Evidence-based recommendations for energy intake in pregnant women with obesity. J Clin Invest. 2019;129:4682-4690.
In 2009, the Institute of Medicine, now known as the National Academy of Medicine, updated its gestational weight gain guideline. This guideline’s major difference, compared with the 1990 guideline, is a specific weight gain range for women with obesity: 5 to 9 kg, or 11 to 20 lb.1 This weight gain range was chosen in part because it allows for a minimum weight gain that supports the growth and development of tissues (fetus, placenta, breast, uterus) and fluids (blood volume, intracellular and extracellular fluid), also known as the “fat-free” mass.
Many studies have since shown not only associations between lower-than-guideline-recommended weight gain and improved pregnancy outcomes (for example, reductions in preeclampsia and cesarean deliveries), but also increases in low birth weight for infants of women with obesity.2,3 Although the weight gain guideline differs based on a woman’s prepregnancy body mass index, the energy requirements, or how many additional calories a woman should consume daily, are the same for all, regardless of weight prior to pregnancy: an increase by 340 to 452 kcal/day in the second and third trimesters.1
Recently, Most and colleagues challenged this recommendation for energy requirements with results from their prospective observational study of 54 women with obesity during pregnancy.4 They aimed to evaluate energy intake with the energy intake-balance method (doubly labeled water and whole-room indirect calorimetry and body composition) according to tests done at 13 to 16 weeks’ gestation and 35 to 37 weeks’ gestation and according to the current National Academy of Medicine gestational weight gain guideline (inadequate, recommended, or excessive weight gain groups).4
Details of the study
Women who participated in this study were recruited from the Pennington Biomedical Research Center in Louisiana and were mostly multiparas (57%); about half had a college degree or higher (52%) and 41% were African American. The investigators found that gestational weight gain in their participants was similar to that found in other large epidemiologic studies in that 67% of women had excessive gestational weight gain.5
Findings. For women who gained the recommended amount of weight (n = 8), mean (SD) daily energy intake was 2,698 (99) kcal/day and energy expenditure was 2,824 (105) kcal/day. Therefore, to meet the recommended amount of weight gain, these women had a negative energy balance (-125  kcal/day). Women with inadequate weight gain
(n = 10) also had a negative energy balance (-262  kcal/day), but the difference was not significantly different compared with that in the recommended gestational weight gain group (P = .08). By contrast, women with excessive gestational weight gain (n = 36) had a mean (SD) positive energy balance of 186 (29) kcal/day.
Fat-free mass and fat mass weight gains. The body weight gains of the fat-free and fat mass compartments also were compared with linear mixed effect models among the 3 weight gain groups. There were no differences in the amount of fat-free mass gained among the 3 weight gain groups (P>.05), but women with excessive gestational weight gain had significantly higher increases in fat mass compared with the other 2 weight gain groups (P<.001).
Pregnancy outcomes. Although there were no differences in cesarean deliveries or birth weight among the 3 weight gain groups, the study was not powered to detect these differences.
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