Energy requirements of pregnancy in rural Thailand.

The energy cost of pregnancy was measured in rural Thai women between 10 wk gestation and term. The energy cost of pregnancy, which includes the increase in basal metabolic rate (BMR), the energy equivalent of maternal fat laid down, and the assumed energy equivalent of fetal fat and fetal and maternal protein, was 202 MJ (1 MJ = 239 kcal). BMR increased by 100 MJ overall and maternal fat gain averaged about 1.3 kg, equivalent to 60 MJ. The energy cost was more than covered by an overall increase in food intake of 238 MJ with little evidence of any complementary reduction in total energy expenditure by reduced physical activity.