Energy Expenditure in the Immediate Postpartum Period: Indirect Calorimetry Versus Predictive Equations

Abstract Objective The study aimed to evaluate the resting energy expenditure (REE) of postpartum women by indirect calorimetry (IC) and provide the most appropriate predictive equations to estimate it. Research Methods & Procedures Cross-sectional study with 79 women in a maternity unit of a Brazilian city hospital. Information regarding age, income, gestational age, and breastfeeding was collected. Height, weight, and body composition were measured. REE was measured by IC (mREE) and predicted using eight equations (pREE). Analysis of comparison, correlation, agreement, and accuracy was performed. Results The median of mREE was 1224.0 (CI 95% 1157.4–1330.0) kcal, and the pREE ranged from 1213.8 (CI 95% 1207.3–1261.9) kcal to 1553.1 (CI 95% 1430.8–1488.5) kcal. There was no difference found in REE between mothers who breastfed versus those who did not (p=0.994); however, there was a positive correlation with lean mass (r=0.336; p=0.003) and weight (r=0.237; p=0.036). The best predictor of REE was the Harris-Benedict equation, with lower difference (p=0.876), better median of adequacy (99.8%), and better ICC (ICC = 0.289). The next best was the Schofield equation, with greater percentage of accuracy (33.3%) and lower opposite agreement (7.6%). Conclusions All predictive equations showed low agreement and accuracy, and, in most cases, the results were overestimated. These findings indicate the need for continued studies on this subject, in order to propose more suitable methods to determine the energy requirements for this population.