Complete review of etiology, clinical course and management of pregnancies complicated by IUGR.

1. IUGR
by La Lura White MD
Maternal Fetal Medicine

2. IUGR
• Fetal growth restriction, (IUGR), is a common
complication of pregnancy.
• Pathologic condition where there is a restriction of
growth in utero, and the fetus does not attain its full
growth potential.
• Complicates ≈5-10% of pregnancies
• Third leading cause of perinatal mortality after anomalies
and prematurity
• 40% of all stillbirths are IUGR

3. IUGR
• Problems in making the diagnosis because there is a lack of
consensus regarding terminology, etiology, and diagnostic
criteria for fetal growth restriction.
• Difficult in differentiating between the fetus that is SGA vs.
IUGR sometimes leading to misdiagnosis.
• Uncertainty surrounding the optimal management and timing
of delivery for the growth-restricted fetus.

4. IUGR
• Often literature will use varying percentiles, 10%, 5% and
even 3%.
• Perinatal mortality inversely proportional to percentile
growth:
1.5% <10%
2.5% < 5th %

5. IUGR

6. IUGR
• Most accepted definition fetuses with IUGR is an
estimated fetal weight that is less than the 10th percentile
for gestational age.
• 70% of fetuses <10% are SGA
• 30% are IUGR

7. IUGR
70%
20% 10%
Uteroplacental
insuffiency:assymetrical Chrosomal,structural, early
infection:symmetrical
Constitutionally small

8. IUGR
• Types of IUGR
• Symmetric IUGR: weight, length and head
circumference are all below the 10 th percentile
• Asymmetric IUGR: weight is below the 10 th percentile
and head circumference and length are preserved, “head
sparing” and the abdomen is small.

9. IUGR
• Normal Rate of Fetal Growth
• 15 weeks = 5 grams/day
• 20 weeks = 10 grams/day
• 30 weeks = 25 grams/day
• 35 weeks = 35 grams/day
• 40 weeks = 15 grams/day
• May vary by race, gender, multiple gestation

10. IUGR
• Normal cellular
development
• Cellular
hyperplasia
• Cellular
hypertrophy

11. IUGR
• 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.

12. IUGR
• 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.

13. IUGR
• Growth inhibition in stage I:
• - Undersized fetus with fewer cells.
• - Normal cell size.
• Result in symmetric IUGR. (1/3)
• Associated conditions:
• - Genetic
• - Congenital anomalies
• - Intrauterine infections
• - Substance abuse
• - Cigarette smoking
• - Therapeutic irradiation

14. IUGR
• 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.(2/3)
• Associated Conditions:
• - Uteroplacental insufficiency.

15. IUGR
• Etiology of IUGR
• Maternal
• Fetal
• Placental

16. IUGR
• Maternal
• Chronic disorder that is associated with vascular disease
• Pregnancy-related hypertensive diseases: (pre-eclampsia with
or without chronic hypertension)
Impaired trophoblastic arteriolar invasion
Atherosis and necrosis
Reduced utero-placental blood flow
• Antiphospholipid syndrome, an acquired immune-meditated
thrombophilia (not seen in hereditary thrombophilia)

17. IUGR
• Maternal
• Pregestational diabetes mellitus
• Renal insufficiency
• Autoimmune disease (eg, systemic lupus erythematous)
• Cyanotic cardic disease
• Substance use and abuse (eg, tabacco, alcohol, cocaine, or narcotics)
• Teratogen exposure (eg, cyclophosphamide, valproic acid, or
antithrombotic drugs)
• Infectious disease (eg, malaria cytomegalovirus rubella,
toxoplasmosis, or syphilis)

18. IUGR
• Fetal
• Multiple gestation
• Congential heart disease
• Gastroschisis
• Genetic and structural disorder
trisomy 13
trisomy 18

19. IUGR
• Placental
• Small placenta
• Fetal/Placental weight ratio
>10
• Placental chronic abruption
• Post-term

20. IUGR
Cord anomalies
Velementous insertion of
the cord.
Major umbilical vessels
separate in the fetal
membranes before reaching
the placental disk.

21. IUGR
• Cord anomalies
• Battledore placenta:
• The cord is attached
to the margin of the
placenta.

22. IUGR
• Epidemiologic studies have revealed that growth-restricted
fetuses are predisposed to the development of cognitive delay
in childhood and diseases in adulthood.
• Barker hypothesis: Increased risk of adult metabolic syndrome
• Obesity
• Type 2 diabetes mellitus
• Coronary artery disease
• Stroke

23. IUGR
• Growth Restriction Intervention Trial
• Only published randomized trial to assess the timing of
delivery of the early preterm (less than 34 weeks of
gestation) growth-restricted fetus.
• Randomized to either the early delivery group (delivery
within 48 hours) or to the expectant management group
(with antepartum surveillance until it was felt that
delivery should not be delayed any longer)
• Betamethasone administration were the same in both
groups

24. IUGR
• Perinatal survival was similar, and at the 6–12-year
follow-up there were no differences in cognitive,
language, behavior, or motor abilities

25. IUGR
• Disproportionate Intrauterine Growth Intervention Trial at
Term
• Women with singleton gestations at or beyond 36 weeks with
suspected fetal growth restriction (defined as an estimated fetal
weight less than the 10th percentile) were randomized to
undergo delivery or expectant management
• Delivery only if indicated
• There were no differences in composite neonatal outcome
between these two groups (study cohort was not large enough)

26. IUGR
• Screening for Fetal Growth Restriction
• Fundal height measured in centimeters (between 24–38 weeks
of gestation) approximates the gestational age
• Up to 85% sensitivity 32-34 weeks
• Ultrasound:
• Biometric measures ( biparietal diameter, head circumference,
abdominal circumference, femur length) yield EFW and %
growth
• EFW may deviate from the birth weight by up to 20% in 95%
of cases
• Standard BW curves will underestimate preterm SGA

27. IUGR
• AC most sensitive
• 3616 preg >25 wks
gestation
• Single us within two
wks delivery
• Predicted <10th%ile for
GA with
• Sens 61%
• Spec 95%
• Ppv 86%
• Npv 83%

28. IUGR
• Ultrasound
• amniotic
fluid
assessment
• <5 oligo

29. IUGR

30. IUGR
• Doppler:
• Blood flowing through the umbilical arteries originates
from the fetus and enters the placenta.
• The flow of blood through the arteries is dependent upon
the strength of the fetal heart contraction and the health of
the placenta.
• Blood returning from the placenta goes through the
umbilical vein to the fetus.

31. IUGR
• Doppler principle based on changes in sound waves
related to the flow velocity of blood traveling through
these vessels.
• The umbilical artery was first used to study this flow
velocity in in 1977.
• The umbilical arterial waveform usually has a "saw
tooth" type pattern with flow always in the forward
direction

32. IUGR
The umbilical artery is evaluated by measuring the blood
flow velocity at peak systole (maximal contraction of the
heart) and peak diastole (maximal relaxation of the heart).
• These values are then computed to derive a ratio.

33. IUGR
• As GA advances, increase blood flow
at diastole means placenta less
resistant.

34. IUGR
• In growth-retarded fetuses and fetuses developing intra-
uterine distress, there is more placental resistance and the
umbilical artery blood velocity waveform usually changes
in a progressive manner.
• Increased resistance, absent end diastolic flow, reverse
flow.

35. IUGR
• Increasing RI values , PI values and S:D ratios
if blood flow during diastole is decreased.

36. IUGR
• absent end diastolic flow

37. IUGR
• reversal of end diastolic
flow (REDF) :

38. IUGR
• notching in late in pregnancy is an indicator
of increased uterine vascular resistance and
impaired uterine circulation’
Mild Severe

39. IUGR
• Prospective Observational Trial to Optimize Pediatric
Health in Intrauterine Growth Restriction (IUGR)
(PORTO STUDY)
• OBJECTIVE:
• National prospective observational multicenter study
• Evaluate which sonographic findings were associated
with perinatal morbidity and mortality in pregnancies
affected by growth restriction (defined as estimated fetal
weight (EFW) <10th centile)
• Am J Obstet Gynecol. 2013 Apr;208(4)

40. IUGR
• STUDY DESIGN:
• Over 1100 consecutive ultrasound-dated singleton pregnancies with
EFW <10th centile were recruited from January 2010 through June
2012.
• A range of IUGR definitions were used, including EFW or abdominal
circumference <10th, <5th, or <3rd centiles
• with or without oligohydramnios
• with or without abnormal umbilical arterial Doppler
• Adverse perinatal outcomes included intraventricular hemorrhage,
periventricular leukomalacia, hypoxic ischemic encephalopathy,
necrotizing enterocolitis, bronchopulmonary dysplasia, sepsis, and
death
• Am J Obstet Gynecol. 2013 Apr;208(4)

41. IUGR
• RESULTS:
• N=1116 fetuses
• 312 (28%) were admitted to neonatal intensive care unit
• 58 (5.2%) were affected by adverse perinatal outcome including 8
mortalities (0.7%)
• The presence of abnormal umbilical Doppler was significantly associated
with adverse outcome, irrespective of EFW or abdominal circumference
measurement.
• The only sonographic weight-related definition consistently associated
with adverse outcome was EFW <3rd centile (P = .0131), all mortalities
had EFW <3rd centile.
• Presence of oligohydramnios was clinically important when combined
with EFW <3rd centile (P = .0066).
• Am J Obstet Gynecol. 2013 Apr;208(4)

42. IUGR
• CONCLUSION:
• Abnormal umbilical artery Doppler and EFW <3rd
centile were strongly and most consistently associated
with adverse perinatal outcome.
• Stricter IUGR cutoffs may be warranted and future
studies should comparing various definitions of IUGR
and management strategies

43. IUGR
• Management
• Serial US q 2-4 weeks as indicated
• Antenatal surveillance with umbilical artery Doppler
velocimetry and antepartum testing (NST,BPP)
• Delivery depends on the underlying etiology and
estimated gestational age

44. IUGR
• Eunice Kennedy Shriver National Institute of Child Health
and Human Development/Society for Maternal-Fetal
Medicine/American College of Obstetricians and
Gynecologists Joint Conference
• Dx fetal growth restriction:
• Delivery at 38 0/7–39 6/7 weeks of gestation isolated fetal
growth restriction
• Delivery at 34 0/7–37 6/7 weeks of gestation in cases of fetal
growth restriction with additional risk factors for adverse
outcome (eg, oligohydramnios, abnormal umbilical artery
Doppler velocimetry results, maternal risk factors, or co-
morbidities)

45. IUGR
• Delivery for fetal growth restriction before 34 weeks:
• Planned at a center with a neonatal intensive care unit
and consultation with a maternal–fetal specialist.
• Antenatal corticosteroids should be administered
• For cases in which delivery occurs before 32 weeks:
• Magnesium sulfate should be considered for fetal and
neonatal neuroprotection.

46. IUGR
Neonatal
Complications
• Low Apgar scores/cord
ph
• Asphyxia
• Meconium aspiration
• Hypoglycemia
• Hypocalcemia
• Polycythemia
• Thrombocytopenia
• Hyperbilirubinemia
• Hypothermia
• Intraventricular
hemorrhage
• Necrotizing enterocolitis,
• Less RDS (?)

47. IUGR

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

49. IUGR
• 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

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

51. IUGR
• Long-term Sequale:
• Up to 50% cognitive disability
• Increased risk of cerebral palsy
• <50% will have chronic growth lag
• <10th percentile at 8 years
• Early IUGR less likely to catch up

52. IUGR
“ I AM A FETUS IN THE WOMB
I FEAR IT MAY BECOME MY TOMB
IF ONLY I COULD GIVE A SHOUT
TO MAKE MY DOCTOR GET ME OUT!”
UNKNOWN MEDICAL STUDENT
DUBLIN, UK 1982