lecture

1. Fetal growth restriction

2. outlines
• Introduction
• Etiology Fetal growth restriction
• Classification
• Diagnosis
• Management
• Complication
• delivery timing
• fetal surveillance

3. Introduction
• IUGR ,FGR, and SGA are terms frequently used interchangeably when
describing the small fetus
• Most often SGA refers to the infant, whereas IUGR to the fetus
• Next to prematurity, FGR is the second leading cause of perinatal
mortality
• PNMR in growth-restricted neonates are 6 to 10 times greater, or 120 per
1000 for all cases of FGR and 80 per 1000 after exclusion of anomalous
infants
• As many as 53% of preterm stillbirths and 26% of term stillbirths have FGR
• In survivors, the incidence of intrapartum asphyxia may be as high as 50%.

4. Definitions
• FGR is suspected when the Sono graphical EFW is below the
tenth percentile (<2SD) for gestational age
• Failure to achieve intrauterine growth potential
• Abdominal circumference <10th percentile
• Flattening of growth curve as judged by clinician

5. REGULATION OF FETAL GROWTH
 Fetal growth is regulated at multiple levels and requires successful
development of the placental interface between maternal and fetal
compartments.
 Fetal growth is divided into three phases.
 Initial phase =hyperplasia occurs in the first 16 weeks and is cx rapid rise in
cell number.
 Second phase -up to 32 weeks’ gestation, includes both cellular
hyperplasia and hypertrophy.
 Third phase -32 weeks onward , cellular hypertrophy,
 most fetal fat and glycogen accumulate.
 fetal-growth rate 5 g/d at 15 weeks’ gestation,15 g/d at 24 weeks’, and 30
g/d at 34 weeks

7. Determinants of optimal Fetal growth
• Distance b/n maternal microvillous and fetal basal layers in the placenta
• Rate of oxygen delivery to the uterus and placental blood flow
• a magnitude of maternal nutrient

8. classification
 Based on absolute birthweight(old)
 low birthweight (LBW; <2500 g),
very low birthweight (VLBW; <1500 g),
extremely low birthweight (ELBW; <1000 g), or
 macrosomia (>4000 g)
 Based birthweight percentile (current)
very small for gestational age (VSGA; <3rd percentile),
small for gestational age (SGA; <10th percentile),
average for gestational age (AGA; 10th to 90th percentile), or
large for gestational age (LGA; >90th percentile).
Draw back
normal birthweight percentile, but abnormal body proportion as a result of differential
growth delay may be missed
Can’t d/t between the const small neonate and growth restricted

9.  Based on body proportion

10. Fetal causes
Teratogenic exposure
Fetal infection ≤10%
 Genetic disorders
 Structural abnormalities
Chromosomal abnormalities may be
detected
o 17% of FGR % ,,,,,, some says
less than 1o%
o 66% of u/s confirmed fetal
malformation
o 53 % of trisomy 13 and 64%
trisomy 18
Placental causes
Primary placental disease
Placental abruption and infarction
Placenta previa
Placental mosaicism

11. Maternal causes
Hypertensive disease
Pregestational diabetes
 Cyanotic cardiac disease
 Autoimmune disease
Restrictive pulmonary ds
Tobacco/substance abuse
High altitude (>10,000 feet)
Malabsorptive ds/malnutrition
 Multiple gestation
Thrombophilia
Drugs eg phenytoin

12. MANIFESTATIONS OF FETAL GROWTH RESTRICTION
Maternal Impacts
o Due to poor placentation ,
 suboptimal maternal volume expansion,
 increased vascular reactivity, and
 “flat” curve on the glucose tolerance test
Lack of spiral and radial A physiologic transformation into low-resistance vessels
(expected at 22-24wks)

13. Fetal Impacts
Metabolic manifestations
Initially after oxygen and nutrient deficit ,fetal supply is compromised first,
whereas placental nutrition is preferentially maintained. Both affected later on
If uterine oxygen delivery falls below a critical value (0.6 mmol/kg/ min ),
Fetal hypoxemia or hypoxia
Hypoglycemia

14. Fetal endocrine manifestations
Low insulin and ILGF –I &II
Low fat stores
Significant elevations of CTRH, ACTH, and cortisol and
Decline in active vitamin D and osteocalcin
Hypothyroidism
Elevations in serum glucagon, adrenaline, and noradrenaline …RF for
adulthood DM

15. Fetal hematologic response
Polycythemia
 Inc Oxygen carrying and the buffering capacity
elevated NRBC
fetal anemia and thrombocytopenia due to placental consumption
Fetal immune manifestation
the cellular and humoral dysfunction (WBC,IG,B-cells,t-lymphocyte…)

16.  Fetal cardiovascular responses
Early -adaptive in nature and result in preferential nutrient to essential
organs
dec umbilical venous flow volume ---earliest feature
Elevation of pulm.V bed and subdiaphragmatic circulation of BFR
myocardium and brachiocephalic circulation has been termed
redistribution,
Late -impairment of cardiac function due to worsened SVR
 loss of diastolic forward flow in the umbilical venous circulation
….hallmark

17. • Finally, myocardial dysfn and cardiac dilatation holosystolic tricuspid
insufficiency and spontaneous FHR decelerations, followed by fetal demise
• Delivery should be below 34wk
 fetal organ Autoregulatory for blood flow
myocardium, adrenal glands, spleen, liver, celiac axis, mesenteric
vessels, and kidney
Fetal behavioral responses
Abn body movements and fetal breathing
BPP abnormality at 28-32wks

18. DIAGNOSTIC TOOLS IN FGR
 After confirming small fetal size, stratification into three patient
groups is of particular importance.
Constitutionally small=not require antenatal surveillance and
intervention
Fetus with chromosomal or congenital anomaly =need family
counselling
Fetus with placental abnormality =benefit from fetal
surveillance and subsequent intervention

19. Fetal Biometry
• Accurate FGR measurement need knowledge of GA
I ) fetal head (BPD, HC and TCD)
asymmetric FGR are not diagnosed late
HC is not affected by external factors unlike BPD
TCD relatively spared from the effects of mild to moderate uteroplacental
dysfunction

20. ii) Abdominal circumference
The AC is the single best measurement for the detection of FGR
higher sensitivity (98% vs. 85%) but lower positive predictive value (PPV) than
the SEFW (36% vs. 51%)
Its sensitivity is further enhanced by serial measurements at least 14 days apart
iii) HC/AC ratio
used for asymmetric FGR
Normally HC/AC ratio > 1 before 32 wks, 1 at 32-34wks , <1 after 34 wks
 the ratio remains high in asymmetric and normal for symmetric
Can detect 70% to 85% of FGR
 sensitivity and PPV is less than AC and SEFW

21. iv) FL/AC ratio
Used w/n difficult measurement in HC( head position-AP, Breech
,oligohydramnios)
The FL/AC ratio is 22 at GA from 21 weeks to term;
An FL/AC ratio greater than 23.5 suggests FGR.

22. v) Sonographic estimated fetal weight (SEFW)
The accuracy of most formulae (±2 standard deviations [SDs]) is ±
10%,
has a lower sensitivity but higher PPV than the AC
The most important calculated ultrasound variable

23. Parameters
Fetal Anatomic Survey
Amniotic Fluid Assessment
-SDP and AFI
 Doppler Velocimetry
1. Arterial Doppler waveforms
• Increase in vascular resistance leads
 S/d ratio, PI ,RI or
absent EDV and REDV
• UA, MCA

24. 2. Venous Doppler parameters
DV,IVC and umbilical
Vi) Invasive Testing
cordocentesis
amniotic fluid R/o TORCH infection and/or karyotyping or
microarray analysis for chromosomal ds

25. SCREENING AND PREVENTION OF FGR
 Maternal History
 Clinical Examination
 Maternal Serum Analytes
 Maternal Doppler Velocimetry
 Integrated Approach to Screening

27. Preventive Strategies
 initiation of low dose ASA at 12-16wks GA decrease PE or FGR by 50-
60%
Indications
poor obstetric history,
unexplained elevations in second-trimester MSAFP,
 flat oral glucose tolerance curves, and
abnormal second-trimester uterine artery Doppler velocimetry

28. MANAGEMENT IN CLINICAL PRACTICE
Conservative managements
Avoid stress, smoking, and alcohol and drug use
Bed rest in the LLP.
Dietary supplementation
Maternal hyperoxygenation
Maternal volume expansion –for low volume status
corticosteroids for lung maturity

29. Fetal surveillance
ASSESSMENT OF FETAL WELL-BEING
Maternal Monitoring of Fetal Activity
Fetal Heart Rate Analysis … NST,CST
Amniotic Fluid Volume
Biophysical Parameters
Doppler Ultrasound
Invasive Fetal Testing

30. Timing of delivery
• Depends on :
• the underlying etiology of FGR (if known)
• Estimated GA
• Others like antenatal fetal surveillance

31. • If delivery is anticipated within 7 days, then administration of
antenatal corticosteroids for fetal lung maturation is indicated in
fetuses diagnosed with growth restriction prior to < 33 6/7 weeks.
• If delivery prior to 32 0/7 is anticipated, then consider
neuroprotection with magnesium sulfate.
• Growth restricted fetuses with abnormal Doppler velocimetry at less
than 32 weeks should be discussed with Maternal Fetal Medicine.

32. Integrated Fetal Testing and Management Protocol