ABSTRACT
Conversely, in growth-restricted fetuses, fetal insulin levels are low, thus further reducing the build up of fetal tissue. Lack of thyroid hormone results in deficiency of skeletal and cerebral maturation, characteristics of cretinism (hypothyroidism) and delayed surfactant production. Cortisol has a limited role in stimulating growth; however, it is essential for the structural and functional development of a wide variety of individual fetal tissues. In the lung, it increases compliance and surfactant release, which ensures that spontaneous breathing can occur at birth. In the fetal liver, cortisol induces beta-receptors and glycogen deposition to maintain a glucose supply to the neonate immediately after birth. In the gut, cortisol is responsible for villi proliferation and induction of digestive
Determinants of birth weight are multifactorial, and reflect the influence of the natural growth potential of the fetus and the intrauterine environment. The latter is controlled both by maternal and placental factors.
