The most recent data on the eff ect of the maternal genome and environment, state of uterine blood fl ow, hypoxia, chronic diseases, maternal smoking, role of the placenta in fetal development are discussed. <...> Questions regarding endocrine regulation of fetus and newborn child will be discussed in the second part of the article. <...> The regulation of normal human fetal growth involves many multidirectional interactions between the mother, placenta, and fetus. <...> The fetus infl uences the provision of maternal nutrients via the placental production of hormones that regulate maternal metabolism. <...> Adequate trophoblast invasion in early pregnancy and increased utero-placental blood fl ow ensure suffi cient growth of the uterus, 504 «Pediatrics. <...> The placenta may respond to fetal endocrine signals to increase transport of maternal nutrients by growth of the placenta, by activation of transport systems, and by production of placental hormones to infl uence maternal physiology and even behavior (Endocrine Reviews, 2006). <...> The Role of Mother in Fetal Growth and Development The maternal genome and the maternal environment: Normal fetal growth involves an increase in cell number during embryonic and fetal development, followed by an increase in cell size, which become dominant after 32 weeks gestation. <...> In the study of pregnancies involving ovum donation, Brooks et al. [36] found that the only factors contributing to birth weight were gestational age and the recipient mother’s weight, whereas the weight of the donor mothers was not related to birth weight. <...> Increased caloric intake is necessary during the second and third trimesters to cope with most fetal and placental growth [222]. <...> Protein intake may be particularly important, and whereas some studies found a relationship between low protein intake in late pregnancy and reduced birth weight [105], others found no eff ect of protein supplementation on fetal growth in undernourished mothers [45]. <...> Nonetheless supplementation of calories or specifi c vitamins to undernourished women may increase birth weight in situations of acute and or chronic starvation [45], for example, folic acid, iron and vitamin A supplementation to pregnant women in Nepal resulted in an increase in mean birth weight of 37 g and a 16% reduction in the rate of low birth weight compared with pregnant <...>