ENERGY REQUIREMENTS DURING PREGNANCY AND LACTATION

Authors: Butte, Nancy; KING, JANET - CHILDREN'S HOSP OAKLAND

Submitted to: Public Health Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/15/2005
Publication Date: 10/16/2005
Citation: Butte, N.F., King, J.C. 2005. Energy requirements during pregnancy and lactation. Public Health Nutrition. 8(7A):1010-1027.

Interpretive Summary: Energy requirements of pregnant and lactating women should support optimal pregnancy outcome and adequate milk production. In this paper, the total energy cost of pregnancy was estimated from changes in basal metabolic rate measured by calorimetry or from changes in total energy expenditure measured by the doubly labeled water method, plus an allowance for the amount of energy deposited in the fetus and maternal tissues. Energy requirements during lactation were estimated from rates of milk production, energy content of human milk, and the amount of energy mobilized if the mother lost weight during lactation. A database was formulated on changes in basal metabolic rate and total energy expenditure and energy deposited during pregnancy. Energy deposition was estimated from a sophisticated multicomponent body composition model based on total body potassium, and fat. The findings indicated that the estimated total cost of pregnancy for women with a mean gestational weight gain of 12.0 kg, was 325 or 321 MJ, distributed as 375, 1200, 1950 kJ/d, for the first, second and third trimesters, respectively. For exclusive breastfeeding, the energy cost of lactation was 2.62 MJ/d based on a mean milk production of 749 g/d, energy content of milk of 2.8 kJ/g, and energetic efficiency of 0.80. In well-nourished women, this may be subsidized by energy from weight loss on the order of 0.72 MJ/d, resulting in a net requirement of 1.9 MJ/d over nonpregnant, nonlactating energy requirements. In conclusion, recommendations for energy intake of pregnant and lactating women should be updated based on recently available data.

Technical Abstract: Objective: To estimate the energy requirements of pregnant and lactating women consistent with optimal pregnancy outcome and adequate milk production. Design: Total energy cost of pregnancy was estimated using the factorial approach from pregnancy-induced increments in basal metabolic rate measured by respiratory calorimetry or from increments in total energy expenditure measured by the doubly labelled water method, plus energy deposition attributed to protein and fat accretion during pregnancy. Setting: Database on changes in basal metabolic rate and total energy expenditure during pregnancy, and increments in protein based on measurements of total body potassium, and fat derived from multi-compartment body composition models was compiled. Energy requirements during lactation were derived from rates of milk production, energy density of human milk, and energy mobilization from tissues. Subjects: Healthy pregnant and lactating women. Results: The estimated total cost of pregnancy for women with a mean gestational weight gain of 12.0 kg, was 321 or 325 MJ, distributed as 375, 1200, 1950 kJ day**-1, for the first, second and third trimesters, respectively. For exclusive breastfeeding, the energy cost of lactation was 2.62 MJ day**-1 based on a mean milk production of 749 g day**-1, energy density of milk of 2.8 kJ g**-1, and energetic efficiency of 0.80. In well-nourished women, this may be subsidized by energy mobilization from tissues on the order of 0.72 MJ day**-1, resulting in a net increment of 1.9 MJ day**-1 over non-pregnant, non-lactating energy requirements. Conclusions: Recommendations for energy intake of pregnant and lactating women should be updated based on recently available data.