Intrauterine Growth Retardation (Restriction) Jignesh Patel, MD Texas Tech University HSC Department of Pediatrics

Definitions IUGR: Failure of normal fetal growth caused by multiple adverse effects on the fetus. SGA: Infant with wt < 10% ile for GA, or > 2 SDs below mean for GA.

Easiest way to think about these terms are IUGR: is a term used by OB to describe a pattern of growth over a period of time. SGA: is a term used by Peds to describe a single point on a growth curve.

Incidence 3 - 10 % of all pregnancies. 20 % of stillborns are growth retarded. 30 % of infants with SIDS were IUGR. 1/3 of infants with BW < 2800 gms are growth retarded and not premature. 9 - 27 % have anatomic and/or genetic abnormalities. Perinatal mortality is 8 - 10 times higher for these fetuses.

Types of IUGR Symmetric IUGR: weight,length and head circumference are all below the 10 th percentile. (33 % of IUGR Infants) Asymmetric IUGR: weight is below the 10 th percentile and head circumference and length are preserved. (55 % of IUGR) Combined type IUGR: Infant may have skeletal shortening, some reduction of soft tissue mass. (12 % of IUGR)

Ponderal Index Way of characterizing the relationship of height to mass for an individual. PI = 1000 x Typical values are 20 to 25. PI is normal in symmetric IUGR. PI is low in asymmetric IUGR. 3 Mass (kgs) Height (cms)

Normal Intrauterine Growth pattern Stage I (Hyperplasia) - 4 to 20 weeks - Rapid mitosis - Increase of DNA content Stage II (Hyperplasia & Hypertrophy) - 20 to 28 weeks - Declining mitosis. - Increase in cell size.

Normal Intrauterine Growth pattern Stage III ( Hypertrophy) - 28 to 40 weeks - Rapid increase in cell size. - Rapid accumulation of fat, muscle and connective tissue. 95% of fetal weight gain occurs during last 20 weeks of gestations.

Etiology Growth inhibition in stage I: - Undersized fetus with fewer cells. - Normal cell size. Result in symmetric IUGR. Associated conditions: - Genetic - Congenital anomalies - Intrauterine infections - Substance abuse - Cigarette smoking - Therapeutic irradiation

Etiology Growth Inhibition in Stage II/III -Decrease in cell size and fetal weight - Less effect on total cell numeric, fetal length, head circumferance. Result in asymmetric IUGR. Associated Conditions: - Uteroplacental insufficiency. Combination above associated mixed type IUGR.

Pathophysiology 1) Fetal factors: Genetic Factors: - Race, ethnicity, nationality - sex ( male weigh 150 -200 gm more than female ) - parity ( primiparous, weigh less than subsequent siblings) -genetic disorders ( Achondroplasia, Russell - silver syn.) Chromosomal anomalies: - Chromosomal deletions - trisomies 13,18 & 21

Pathophysiology Congenital malformations: examples:Anencephaly, GI atresia, potter’s syndrome, and pancreatic agenesis. Fetal Cardiovascular anomalies Congenital Infections: mainly TORCH infections. Inborn error of metabolism: - Transient neonatal diabetes - Galactosemia - PKU

Pathophysiology 2) Maternal Factors: Decrease Uteroplacental blood flow: - Pre eclampsia / eclampsia - chronic renovascular disease - Chronic hypertension Maternal malnutrition Multiple pregnancy Drugs - Cigarettes, alcohol, heroin, cocaine - Teratogens, antimetabolites and therapeutic agents such as trimethadione, warfarin, phenytoin

Pathophysiology Maternal hypoxemia - Hemoglobinopathies Others - High altitudes Others - Short stature - Younger or older age (<15 and >45) - Low socioeconomic class - Primiparity - Grand multiparity - Low pregnancy weight - Previous h/o preterm IUGR baby - Chronic illness ( DM, renal failure, cyanotic heart disease etc.)

Pathophysiology 3) Placental Factors: Placental insufficiency ( most imp in 3rd trimester) Anatomic problems: Multiple infarcts Aberrant cord insertions Umbilical vascular thrombosis & hemangiomas Premature placental separation Small Placenta

Postnatal Assessment Growth parameters: weight, height, HC Assess GA with Ballard score. Plotted growth parameters in growth chart

Physical Appearance

Physical appearance: Heads are disproportionately large for their trunks and extremities Facial appearance has been likened to that of a “wizened old man”. Long nails. Scaphoid abdomen

Signs of recent wasting - soft tissue wasting - diminished skin fold thickness - decrease breast tissue - reduced thigh circumference Signs of long term growth failure - Widened skull sutures, large fontanelles - shortened crown – heel length - delayed development of epiphyses Comparison to premature infants,IUGR has brain and heart larger in proportion to the body weight, in contrast the liver, spleen, adrenals and thymus are smaller.

Complication Hypoxia Thermoregulation - Perinatal asphyxia - Persistent pulmonary hypertension - meconium aspiration Thermoregulation - Hypothermia due to diminished subcutaneous fat and elevated surface/volume ratio

Complications Metabolic - Hypoglycemia - result from inadequate glycogen stores. - diminished gluconeogenesis. - increased BMR - Hypocalcemia - due to high serum glucagon level, which stimulate calcitonin excretion

Complications Hematologic Immunologic - hyperviscosity and polycythemia due to increase erythropoietin level sec. to hypoxia Immunologic - IUGR have increased protein catabolism and decreased in protein, prealbumin and immunoglobulins, which decreased humoral and cellular immunity.

Management Antenatal diagnosis and management is the key to proper management of IUGR Delivery and Resuscitation - appropriate timing of delivery - skilled resuscitation should be available - prevention of heat loss Hypoglycemia - close monitoring of blood glucose - early treatment ( IV dextrose, early feeding )

Management Hematological Disorder - central Hct to detect polycythemia - CBC with diff to r/o leukopenia or thrombocytopenia Congenital infection - infant should be examined for signs of congenital infection (eg.rash, microcephaly hepatosplenomegaly, lymphadenopathy, cardiac anomalies etc….) - TORCH titer screening - Viral cx of urine, nasopharynx - Head CT to r/o calcification

Management Genetic anomalies - screening as indicated by physical exam - chromosomal analysis (infant with dysmorphic features) Others - serum calcium to r/o hypocalcemia - fractionated bilirubin sec to polycythmia, congenital infection - urine, meconium tox for substance abuse

Management Early feeding and caloric intake should be 100-120 kcal/kg/d Developmental and growth f/u in all IUGR infants

Outcome Symmetric vs. Asymmetric IUGR - symmetric has poor outcome compare to asymmetric Preterm IUGR has high incidence of abnormalities IUGR with chromosomal disease has 100% incidence of handicap Congenital infection has poor outcome - handicap rate > 50% IUGR has higher rate of learning disability.

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