6 - Abnormalities of Fetal Growth

Abstract

Normal fetal growth is determined by a number of factors, including genetic potential, the ability of the mother to provide sufficient nutrients, the ability of the placenta to transfer nutrients, and intrauterine hormones and growth factors. The pattern of normal fetal growth involves rapid increases in fetal weight, length, and head circumference during the last half of gestation. During the last trimester, the human fetus accumulates significant amounts of fat. The weight for gestational measurements among populations has been shown to increase over time, and thus standards for normal fetal growth require periodic re-evaluation for clinical relevance. These increases in weight for gestational age over time are attributed to improvements in living conditions and maternal nutrition and changes in obstetric management. Variations in fetal growth have been identified in diverse populations and are associated with geographic locations (sea level versus high altitude), populations (white, African-American, Latino), maternal constitutional factors, parity, maternal nutrition, fetal gender, and multiple gestations. In this chapter, we discuss these factors in greater detail and critically review the long-term effects of abnormal fetal growth.