ABSTRACT
During the first two thirds of gestation, coinciding with a minimal weight accretion by the conceptus, the mother prepares herself to maintain the rapid fetal growth that takes place during the last trimester of pregnancy. In fact, during early gestation maternal weight gain is greater than the simple intrauterine growth and weight gain. In this phase, the mother conserves more exogenous nutrients whenever she eats, and this anabolic condition is especially manifested in her accumulation of fat deposits. In the later part of gestation, the rapid fetal growth is sustained by the placental transfer from the mother of a variety of substrates; of these glucose is the most abundant. This intense loss of nutrients from maternal circulation is not compensated by her hyperphagia and seems to contribute to a switch to a net catabolic state which is especially evident in adipose tissue and becomes accelerated when food is withheld. Under this condition, exaggerated ketogenesis and gluconeogenesis actively contribute to the availability of fuels to the fetus.
