Sue Ann Smith, MD Neonatologist Doernbecher Neonatal Care Center SGA/IUGR Sue Ann Smith, MD Neonatologist Doernbecher Neonatal Care Center

Intrauterine Growth Restriction (IUGR) No universal definition Any baby who does not achieve intrauterine growth potential Usually defined as < 2 SD below the mean for weight.

Small for Gestational Age (SGA) Usually defined as <2SD or <10th % for growth parameters Babies <3% are at greatest risk of morbidity and mortality. Babies who are constitutionally small are at less risk of complications than those who are SGA from pathologic process.

Etiology of SGA Maternal Factors Placental Factors Fetal Factors

Maternal Factors Genetic size Demographics Age (extremes of reproductive age) Race Socioeconomic status Underweight before pregnancy or malnutrition Chronic disease Exposure to teratogens (EtOH, drugs, radiation, etc.)

Maternal Factors (cont.) Factors that interfere with placental flow and function Postmaturity Multiple gestation Uterine anomalies Thrombotic disease High altitude environment Smoking Cocaine Heart disease Renal disease Hypertension Pulmonary disease Hemoglobinopathies Collagen-vascular disease Diabetes

Placental Factors Malformations – vascular Chorioangioma Infarction Abruption Previa Abnormal trophoblast invasion

Fetal Factors Constitutional – genetically small, but genetically normal Chromosomal abnormality – only about 5% of SGA babies Malformations – CNS, skeletal, gastroschisis Congenital infections – CMV, rubella

Characteristics of IUGR Symmetric Early onset Constitutional or “normal” small Decreased growth potential Normal ponderal index Lower risk for transitional problems Brain symmetrical to body Examples Genetic causes, chromosomal TORCH infections Anomalad Syndromes

Characteristics of IUGR Asymmetric Late onset Environmental Growth arrest Higher risk for transitional problems Brain sparing Examples Chronic hypoxia Preeclampsia (PIH, PET) Chronic hypertension Malnutrition

Neonatal Complications of IUGR Mortality rate 5-20x that of AGA Perinatal asphyxia Abnormal temperature regulation Hypoglycemia Hyperviscosity-polycythemia syndrome Altered immunity Thrombocytopenia

Neonatal Complications of IUGR(cont) Pulmonary hemorrhage PPHN Hypocalcemia

Evaluation of SGA Newborn Careful physical examination Measure & plot head circumference & length CBC with differential and platelet count Monitor glucose carefully Further evaluation? Urine for CMV TORCH titers Liver function tests Head Ultrasound

“Long term” Morbidity of IUGR Factors associated with abnormal outcome ? Microcephaly Hypoxic ischemic encephalopathy Symptomatic hypoglycemia Symptomatic hyperviscosity

Growth Consequences of IUGR Height at 4 years Weight at 4 years 50 40 20 30 10 >90 50-90 10-50 <10 50 40 20 30 10 >90 50-90 10-50 <10 Percent Percent Percent Percent Term AGA Term SGA Preterm SGA

Growth Consequences of IUGR Head Circumference at 4 years 50 40 20 30 10 >90 50-90 10-50 <10 Percent Term AGA Term SGA Preterm SGA

Fetal Origins of Adult Diseases ? Coronary artery disease correlates inversely with birth weight Rate of non-insulin dependent diabetes mellitus is highest in the “thinnest” babies at birth (low ponderal index) High serum cholesterol are linked to disproportionate size at birth (body smaller than head) Increased rate of hypertension in infants who were thin, short, &/or proportionately small at birth