Objectives: Our purpose was to test whether energy-sensitive adjustments in gestational metabolism, previously observed in studies of Gambian and British women, are a general phenomenon and to define the nutritional factors that direct them.
Study design: Retrospective analysis of data on basal metabolic rate and fat deposition in 360 pregnancies from 10 studies in a wide range of nutritional settings was performed.
Results: The energy costs of pregnancy varied widely between different communities: maintenance costs from -45 to +210 MJ, fat deposition from -23 to +267 MJ, and total energy costs from -20 to +523 MJ. Total costs were correlated with prepregnancy fatness (r = 0.80, p < 0.01) and pregnancy weight gain (r = 0.94, p < 0.001). Marginally nourished women conserved energy by suppressing metabolic rate and by gaining little fat.
Conclusions: The energy needs of pregnancy are modulated over a wide range in response to maternal energy status. This may be an important means of protecting fetal growth.
PIP: Fetal growth within pregnant women requires energy above and beyond that typically required to maintain normal function in the nonpregnant human female. Many women, however, especially in comparatively poor countries, are undernourished and can not freely secure and consume the additional nutrients which their bodies request. These women still manage to bear children successfully despite the nutritional constraints. The authors previously conducted parallel studies of the energy costs of pregnancy in poor women from a group of rural Gambian villages and in affluent women from Cambridge, United Kingdom. They identified important energy-sparing metabolic strategies which, in response to the energy stresses of pregnancy, help achieve a successful outcome under marginal nutritional conditions. This more recent study was conducted to test whether energy-sensitive adjustments in gestational metabolism observed in the former studies of Gambian and British women are a general phenomenon and to define the nutritional factors which direct them. Data are analyzed from all published studies in which the energy costs of pregnancy have been measured. This covers 360 pregnancies from the Netherlands, Sweden, Scotland, England, the Philippines, Thailand, and the Gambia. It is concluded that the energy needs of pregnancy are modulated over a wide range in response to maternal energy status. Energy costs of pregnancy varied widely between different communities, total costs were correlated with prepregnancy fatness and pregnancy weight gain, and marginally nourished women conserved energy by suppressing metabolic rate and by gaining little fat.