Endocrinologic investigations during pregnancy have focused in the last decades on placental hormones, the maternal endocrine system and maternal fetal interactions. Less is known about the fetus itself and the interaction of fetal hormonal response and physiological parameters. In this book physiologists, pediatricians and obstetricians active in experimental studies in both physiology and endocrinology combine both aspects of investigations. Historical remarks on the endocrine development of the fetus are followed by observations of the hormonal control of the cardiovascular system. Basic mechanisms of fetal endocrine control such as brain development, fetal growth, fetal behaviour, and thermoregulation are given particular consideration. Finally, carbohydrate metabolism and the mechanism of parturition are outlined.