ABSTRACT
Despite major progress made in obstetrics over recent decades, there is still a lack of knowledge on how to manage the macrosomic fetus. Macrosomic fetuses are at increased risk of complications during pregnancy, childbirth, and postnatal life in the short and long term. The chapter presents risks related to pregnancy. The macrosomic fetus is in a fragile balance; its large constitution and enhanced metabolism result in an increased oxygen need with respect to an average-weight fetus, while its placenta is not equally developed to accommodate this request and may induce a chronic status of fetal hypoxemia. The two main risk factors for macrosomia are obesity and gestational diabetes and, when present, may complicate the clinical management at term. In addition, if diabetes is the cause of macrosomia, reactive fetal hyperinsulinism acts on the placenta. When considering an elective early delivery because of fetal macrosomia, it must be taken into account whether there is sufficient fetal maturation.
