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United States Department of Agriculture

Agricultural Research Service

Title: Energy Requirements During Pregnancy Based on Total Energy Expenditure and Energy Deposition

Authors
item Butte, Nancy
item Wong, William
item Treuth, Margarita - JOHNS HOPKINS UNIV
item Ellis, Kenneth
item Smith, O'Brian

Submitted to: American Journal of Clinical Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 27, 2004
Publication Date: June 1, 2004
Citation: Butte, N.F., Wong, W.W., Treuth, M.S., Ellis, K.J., Smith, O.E. 2004. Energy requirements during pregnancy based on total energy expenditure and energy deposition. American Journal of Clinical Nutrition. 79(6):1078-1087.

Interpretive Summary: Energy requirements (ER) during pregnancy are controversial because of uncertainties regarding how much body fat is deposited in normal pregnancies and whether pregnant women reduce their level of physical activity as pregnancy progresses. This study was designed to estimate ER of healthy underweight, normal-weight and overweight pregnant women. ER of 63 women (n=17 low-body mass index (BMI), n=34 normal-BMI, and n=12 high-BMI) were estimated at 0, 9, 22, 36 wk of pregnancy, and at 27 wk postpartum. ER were estimated from changes in rates of energy expenditure and the amount of energy deposited during pregnancy in the form of fat and protein. Sophisticated methods of respiratory calorimetry and doubly labeled water were used to measure energy expenditure during rest (basal metabolic rate, BMR) and activity (activity energy expendiure, AEE), as well as throughout the entire day (total energy expenditure, TEE). BMR increased gradually throughout pregnancy at a mean rate of 11 kcal/gestational wk, whereas TEE increased by 5 kcal/gestational wk, indicating a slight decline in AEE as pregnancy progressed. Although total protein deposition did not differ by BMI group, FM deposition did (5.3, 4.6, 8.4 kg FM in low-, normal-, and high-BMI groups. Thus, energy costs differed by BMI group and were excessive in the high BMI group. In the normal BMI group, ER increased negligibly in the first trimester, 350 kcal/d in the second trimester and 500 kcal/d in the third trimester. Extra energy intake is required by healthy pregnant women to support adequate weight gain and the rise in basal energy expenditure, which are not totally offset by reductions in physical activity.

Technical Abstract: Energy requirements (ER) during pregnancy remain controversial because of uncertainties regarding maternal fat deposition and reductions in physical activity. This study was designed to estimate ER of healthy underweight, normal-weight and overweight pregnant women and to explore energetic adaptations to pregnancy. ER of 63 women (n=17 low-body mass index (BMI), n=34 normal-BMI, and n=12 high-BMI) were estimated at 0, 9, 22, 36 wk of pregnancy, and at 27 wk postpartum. Basal metabolic rate (BMR) was measured by calorimetry, total energy expenditure (TEE) by doubly labeled water and activity energy expenditure (AEE) as TEE-BMR. Energy deposition was calculated from changes in body protein and fat. ER was equal to the sum of TEE and energy deposition. BMR increased gradually throughout pregnancy at a mean rate of 10.7 ± 5.4 kcal/gestational wk, whereas TEE increased by 5.2 ± 12.8 kcal/gestational wk, indicating a slight decline in AEE. Energy costs of pregnancy depended on BMI group. Although total protein deposition did not differ sygnificantlly by BMI group (mean for the 3 groups:611 g protein), FM deposition did (5.3, 4.6, and 8.4 kg FM in low-, normal-, and high-BMI groups; P=0.02). Thus, energy costs differed significantly by BMI group (P=0.02). In the normal BMI group, ER increased negligibly in the first trimester, 350 kcal/d in the second trimester and 500 kcal/d in the third trimester. Extra energy intake is required by healthy pregnant women to support adequate gestational weight gain and the rise in BMR which are not totally offset by reductions in AEE.

Last Modified: 11/25/2014
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