SGA/IUGR

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

2. 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.

3. 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.

4. Etiology of SGA • Maternal Factors • Placental Factors • Fetal Factors

5. 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.)

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

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

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

9. 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

10. 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

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

12. Neonatal Complications of IUGR(cont) • Pulmonary hemorrhage • PPHN • Hypocalcemia

13. 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

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

15. 50 50 40 40 30 30 20 20 10 10 <10 10-50 50-90 >90 <10 10-50 50-90 >90 Term AGA Term SGA Preterm SGA Growth Consequences of IUGR Height at 4 years Weight at 4 years Percent Percent Percent Percent

16. 50 40 30 20 10 <10 10-50 50-90 >90 Term AGA Term SGA Preterm SGA Growth Consequences of IUGR Head Circumference at 4 years Percent

17. 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