Small for Gestational Age (Archived)

Small for gestational age (SGA) is defined as a birth weight of less than the 10th percentile for gestational age. SGA infants are categorized into 2 major groups: constitutionally normal infants who are SGA and infants who are SGA because of growth restriction with a birth weight lower than the expected optimal birth weight. The constitutionally normal infants have normal birth weights less than the 10th percentile because of inherent factors such as maternal height, weight, ethnicity, and parity. There is no increased risk of perinatal mortality and morbidity in these infants. SGA and fetal growth restriction (FGR) are interchangeable but not synonymous. Many infants who are SGA have FGR, and many infants with FGR are SGA. However, SGA cannot be used as a marker for FGR because some infants with FGR have a birth weight greater than the 10th percentile. Therefore, in making a distinction between SGA and FGR, it is important to use fetal growth curves customized based on constitutional factors to distinguish normal SGA infants from those with FGR. This topic focused on infants with SGA secondary to FGR (FGR SGA). The prevalence of FGR SGA in high-income countries such as the United States and Australia is approximately 11%; however, in low and middle-income countries, an estimated 32.5 million infants were born FGR SGA, and the majority of these infants, an estimated 53% (16.8 million), were born in South Asia. The causes of FGR SGA are diverse and range from fetal, maternal, uterine/placental to demographic factors. Recent studies have shown that catch-up growth is possible, and normal size can be reached at 9 months in about 80% of newborns with FGR SGA. However, newborns with FGR SGA are at increased risk for other complications such as prematurity, neonatal asphyxia, hypothermia, hypoglycemia, hypocalcemia, polycythemia, sepsis, and death. The purpose of this review is to highlight the current trends in the management of children born with FGR SGA.