Resting energy expenditure in pregnant Japanese women.

The subjects were 160 pregnant women with no complications who were examined with indirect calorimetry by a single observer; 20 healthy age-matched non-pregnant women were used as controls. Assessment was performed 12 hours after oral intake of food. Each measurement of resting energy expenditure divided by the body surface area was analyzed and compared with that of the controls. In pregnant women, the mean resting energy expenditure divided by the body surface area did not significantly increase until 32 weeks' gestation. Energy expenditure increased significantly by about 300 approximately 600 kJ/m(2) between before 31 weeks' gestation and the end of pregnancy. Significant changes occurred in the 32 approximately 35 and 36 approximately 40 weeks' gestational stages (3,790+/-370,4,110+/-385 kJ/m(2)) (p<0.05). Resting energy expenditure increases at conception, and does not increase until 32 weeks' gestation, but increases gradually from 32 weeks' gestation to term in normal pregnant women as assessed by indirect calorimetry.