Energy-sparing strategies to protect human fetal growth.

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.