Intrauterine Growth Restriction

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Intrauterine Growth Restriction (IUGR):

Intrauterine Growth Restriction (IUGR) Fahmy Group C Batch 10


Definitions IUGR - fetus is unable to achieve its genetically determined potential size Small for gestational age (SGA) - growth at the 10th or less percentile for weight of all fetuses at that gestational age 2

Slide 3:

Not all fetuses that are SGA are pathologically growth restricted ( may be constitutionally small) N ot all fetuses that have not met their genetic growth potential are in less than the 10th percentile for estimated fetal weight 3

Slide 4:

Distribution of small fetuses (≤ 10 th percentile for growth) 4

IUGR occurs when..:

IUGR occurs when.. gas exchange and nutrient delivery to the fetus are not sufficient to allow it to thrive in utero , primarily because of maternal disease causing ↓ oxygen-carrying capacity dysfunctional oxygen delivery system secondary to maternal vascular disease placental damage resulting from maternal disease 5

Maternal causes of IUGR:

Maternal causes of IUGR Chronic hypertension Pregnancy-associated hypertension Cyanotic heart disease Diabetes Hemoglobinopathies Autoimmune disease Protein-calorie malnutrition Smoking Substance abuse Uterine malformations Thrombophilias Prolonged high-altitude exposure 6

Placental or Umbilical cord causes of IUGR:

Placental or Umbilical cord causes of IUGR Twin-to-twin transfusion syndrome Placental abnormalities Chronic abruption Placenta previa Abnormal cord insertion Cord anomalie s Multiple gestations 7

Perinatal complications:

Perinatal complications fetal morbidity and mortality iatrogenic prematurity fetal compromise in labor need for induction of labor cesarean delivery 8


Neonatally .. ↑ risk for neonatal morbidity ↑ rates necrotizing enterocolitis Thrombocytopenia temperature instability renal failure 9

Brain-sparing effect:

Brain-sparing effect limited nutritional reserve → fetus redistributes blood flow to sustain function + development of vital organs ↑ relative blood flow to the brain, heart, adrenals, and placenta ↓ relative flow to the bone marrow, muscles, lungs, GI tract, and kidneys → Relatively normal sized head but reduced abdominal girth 10

Symmetric vs Asymmetric growth:

S ymmetric vs Asymmetric growth Symmetrically small fetuses ← global insult ( eg , aneuploidy , viral infection, fetal alcohol syndrome) Asymmetrically small fetuses ← imposed restriction in nutrient and gas exchange 11

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Perinatal Events and Outcomes ( Dashe et al, September 2000) 12

Diagnosing IUGR..:

Diagnosing IUGR.. Estimated Fetal Weight (EFW) ≤ 10th percentile → identify fetuses at risk review the dating criteria before offering intervention to treat growth restriction in a fetus If dates are uncertain → obtain a second growth assessment over a 2 to 4 week interval 13

Screening fetus for growth restriction:

Screening fetus for growth restriction serial sonography 18 - 20 wk → confirm dates, evaluate anomalies, identify multiple gestations 28 - 32 wk → fetal growth, evidence of asymmetry, and stigmata of brain-sparing physiology ( eg, oligohydramnios, abnormal Doppler findings) 14

Screening fetus for growth restriction (2):

Screening fetus for growth restriction (2) symphysis–fundal height measurements a discrepancy of > 3 cm between observed and expected measurements (1) → growth evaluation using ultrasound (1) Jelks A, Cifuentes R, Ross MG. Clinician bias in fundal height measurement. Obstet Gynecol . Oct 2007;110(4):892-9 15


Biometry Assess individual parameters normal head and femur measurements + abdominal circumference (AC) < 2 standard deviations below the mean (a cut off to consider a fetus asymmetric) 16

Amniotic Fluid volumes:

Amniotic Fluid volumes amniotic fluid index (AFI) < 5 → rate of IUGR is 19% , AFI > 5 → 9% (1) Increased risk of IUGR in borderline amniotic fluid (AFI of 5 -10) relative to a group of normal fetuses with AFI > 10 (2) Chauhan SP, Scardo JA, Hendrix NW, et al. Accuracy of sonographically estimated fetal weight with and without oligohydramnios . A case-control study. J Reprod Med . Nov 1999;44(11):969-73 Banks EH, Miller DA. Perinatal risks associated with borderline amniotic fluid index. Am J Obstet Gynecol . Jun 1999;180(6 Pt 1):1461-3 17

Maximum Vertical Pocket (MVP):

M aximum V ertical Pocket (MVP) ↑ rate of IUGR among fetuses with decreasing MVP values MVP <2 cm was associated with an IUGR rate of 20% MVP <1 cm was associated with an IUGR rate of 39% 18

Umbilical Artery (UA) Doppler measurement:

Umbilical Artery (UA) Doppler measurement Measures systolic-to-diastolic ratio of flow - changes from a baseline value to an elevated value with worsening disease As insufficiency progresses → end-diastolic velocity is lost and, finally, reversed status of UA blood flow corroborates the diagnosis of IUGR and provides early evidence of circulatory abnormalities in the fetus 19

Slide 20:

20 Diastolic flow reversal of umbilical artery

Other investigations modalities:

Other investigations modalities Middle cerebral artery (MCA) Doppler Venous Doppler waveforms Three-dimensional ultrasonography 21

Therapeutic options:

Therapeutic options 3 interventions (1) were shown to be helpful behavioral strategies to quit smoking → lower rate of low birth weight in babies at term among mothers who smoke balanced nutritional supplements in undernourished women + magnesium & folate supplementation ↓ the rate of SGA newborns if malaria is the etiologic agent, maternal treatment of malaria can ↑ fetal growth (1) Gülmezoglu M, de Onis M, Villar J. Effectiveness of interventions to prevent or treat impaired fetal growth. Obstet Gynecol Surv . Feb 1997;52(2):139-49 22

Administration of Steroids:

A dministration of Steroids ↓ neonatal morbidity and mortality of premature fetuses when delivery is anticipated Benefits of maternal prenatal glucocorticoid administration in growth-restricted fetuses similar to those found in gestational age–matched, normally grown fetuses 23

Goal in Management if IUGR:

Goal in Management if IUGR to deliver the most mature fetus in the best physiological condition possible while minimizing maternal risk requires use of antenatal testing with the hope of identifying the fetus with IUGR before it becomes acidotic 24

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Sample protocol for antenatal testing for intrauterine growth restriction ≥ 32 weeks *diagnosis of severe IUGR before 32 weeks' gestation is associated with a poor prognosis 25


Conclusion R emains a challenging problem Most cases occur in pregnancies in which no risk factors are present → must be alert to the possibility of a growth disturbance in all pregnancies No single measurement helps secure the diagnosis Goals → to optimize timing of delivery, to minimize hypoxemia, maximize gestational age and maternal outcome 26