Fetal-Growth-Disorders

1. FETAL GROWTH
DISORDERS
EDALYN RAMOS CAPILI
METROPOLITAN MEDICAL CENTER
COLLEGE OF MEDICINE
MAY 15, 2018

2. FETAL GROWTH
• characterized by sequential patterns of tissue &
organ growth, differentiation, & maturation
• ability to growth restrict may be adaptive rather
than pathological
• determined by maternal provision of substrate,
placental transfer of substrates, & fetal growth
potential governed by the genome
• insulin & IGFs– important in regulation of fetal
growth and weight gain
• dependent on adequate supply of nutrients

3. FETAL GROWTH PHASES
HYPERPLASIA
• First 16 weeks
• Rapid increase
in cell number
• 5 g/day at 15
weeks’
gestation
HYPERPLASIA
AND
HYPERTROPHY
• Up to 32 weeks’
gestation
• 15-20 g/day at
24 weeks
HYPERTROPHY
• After 32 weeks
• Fetal fat and
glycogen are
accumulated
• 30-35 g/day at
34 weeks

4. NORMAL BIRTHWEIGHT
Normative data for fetal growth based on
birthweight vary with ethnicity and
geographic region.
Infants born to women who reside at high
altitudes are smaller than those born at
sea level.
Birthweight doesn’t define the rate of fetal
growth. Rate or velocity can be estimated by
serial sonographic anthropometry.

5. FETAL–GROWTH
RESTRICTION
• Low-birthweight newborns who
are small for gestational age
• BWs <10th percentile, are not
pathologically growth restricted,
but are small because of
normal biological factors.
• 25-60% SGA infants are
appropriately grown when
maternal ethnic group, parity,
weight, & height are considered

6. SYMMETRICAL VS
ASYMMETRICAL
• Campbell and Thoms (1977) described use of
sonographically determined head-to-abdomen
circumference ratio (HC/AC).
• Onset or etiology of fetal insult has been linked
to either type of growth restriction.
• Symmetrical growth restriction: early insult 
decrease in cell number and size
• Asymmetrical growth restriction: late insult
(placental insufficiency from HPN)

7. SYMMETRICAL VS
ASYMMETRICAL
• Diminished glucose transfer and hepatic
storage would affect cell size and not number,
and fetal abdominal circumference—which
reflects liver size—would be reduced.
• Somatic-growth restriction  shunting of oxygen
and nutrients to the brain
• Because of brain-sparing effects, asymmetrical
fetuses were thought to be protected from the
full effects of growth restriction.

8. PLACENTAL
ABNORMALITIES
• Rogers and coworkers (1999) observed that
implantation site disorders (incomplete
trophoblastic invasion) are associated with
fetal growth restriction & hypertensive disorders.
• Atrial natriuretic peptide converting enzyme
(corrin), has been shown to play critical role in
trophoblastic invasion and remodeling of the
uterine spiral arteries.
• Maternal rejection of the “paternal semiallograft”

9. LONG-TERM SEQUELAE
Fetal-growth restriction affect organ development,
particularly that of the heart. Individuals with low
birthweight demonstrate cardiac structural
changes and dysfunction persisting through
childhood, adolescence, and adulthood.
Deficient fetal growth is also associated with
postnatal structural and functional renal changes.
Association of low birthweight with disordered
nephrogenesis, renal dysfunction, chronic kidney
disease, and hypertension.

10. RISK FACTORS AND
ETIOLOGIES

11. DIAGNOSIS
Effective screening for IUGR requires accurate dating,
review of the mother’s menstrual history, relevant
assisted reproductive technology information, and either
1st trimester or early 2nd trimester dating ultrasound.
Symphysis-fundal height determination is of limited
value in routine obstetrical care, but continues to be the
only physical examination screening test available.
Determining whether IUGR is symmetric or asymmetric
is of less clinical importance than careful re-evaluation
of fetal anatomy and uterine and umbilical artery
Doppler studies.
SOGC CLINICAL PRACTICE GUIDELINE, 2013

12. RECOGNITION OF FETAL-
GROWTH RESTRICTION
UTERINE FUNDAL
HEIGHT
• Between 18 and 30
weeks’ gestation,
uterine fundal height in
centimeters coincides
within 2 weeks of
gestational age.
• If the measurement is
>2-3 cm from expected
height, inappropriate
fetal growth is
suspected.
SONOGRAPHIC
MEASUREMENTS OF
FETAL SIZE
• Initial sonographic
examination: 16-20
weeks’ gestation,
• Increasingly in 1st tri—to
establish gestational
age & identify anomalies
• Femur length is the
easiest and the most
reproducible.

13. RECOGNITION OF FETAL-
GROWTH RESTRICTION
AMNIONIC FLUID
VOLUME
MEASUREMENT
• Association between
pathological fetal-growth
restriction and
oligohydramnios
• Hypoxia & diminished
renal blood flow has
been hypothesized as
explanation for
oligohydramnios.
DOPPLER
VELOCIMETRY
• Absent or reversed
end-diastolic flow—
been uniquely linked w/
fetal-growth restriction
• Improve clinical
outcomes
• Recommended in
management of fetal-
growth restriction as
adjunct to standard
surveillance techniques

14. PREVENTION
Before conception, w/ optimization of maternal
medical conditions, medications, & nutrition.
Smoking cessation
Antimalarial prophylaxis for women living in
endemic areas.
Accurate dating is essential in early pregnancy.
Serial sonographic evaluations are used.

15. MANAGEMENT
Patient counseling and prenatal diagnostic testing
are indicated.
Pregnancies complicated by fetal-growth
restriction and at risk for birth <34 weeks receive
antenatal corticosteroids for pulmonary maturation.
Near Term: Delivery between 34 and 37 weeks when
there are concurrent conditions such as
oligohydramnios.
Remote from Term: Nutrient supplementation,
plasma volume expansion, oxygen,
antihypertensives, heparin, & aspirin  ineffective

16. MANAGEMENT

17. SUMMARY
Fetal-growth restriction  result of placental
insufficiency d/t faulty maternal perfusion and/or
reduction of functional placenta
Diminished amnionic fluid volume increases
likelihood of cord compression during labor.
Woman w/ growth-restricted fetus should
undergo “high-risk” intrapartum monitoring.
Frequency of cesarean delivery is increased.
Care for the newborn should be provided
immediately by an attendant who can skillfully
clear the airway and ventilate infant as needed.

18. MACROSOMIA
• birthweights that exceed certain
percentiles for a given population
• large-for-gestational age (LGA)
birthweight
• infants >90th percentile for a
given gestational week
• newborns who weigh ≥4500 g at
birth (ACOG 2013)
• excessive glycemia; excessive
transfer of lipids to fetus

19. RISK FACTORS FOR
FETAL OVERGROWTH
Obesity, Large size of parents
Diabetes—gestational and type 2
Post term gestation
Multiparity
Previous macrosomic infant
Advancing maternal age
Racial and ethnic factors

20. MATERNAL AND
PERINATAL MORBIDITY
Neonates with BW of at least 4500 g have
been reported to have cesarean delivery
rates >50%.
Shoulder dystocia reported to be as high
as 17% (BW of 4500 g) and 23% (BW of
5000 g).
Complications: Postpartum hemorrhage,
Perineal laceration, and Maternal
infection, Increased neonatal fat mass,
Morphological heart changes

21. DIAGNOSIS
Estimates provided by measurements
of the head, femur, and abdomen:
• REASONABLY ACCURATE in predicting the wt
of small, preterm fetuses
• LESS VALID in predicting the wt of large fetuses
Sonographic estimation of fetal wt is
UNRELIABLE, and its routine use to identify
macrosomia is NOT RECOMMENDED.

22. MANAGEMENT
PROPHYLACTIC
LABOR INDUCTION
• Nondiabetic women
• ACOG 2013, doesn’t
support a policy for
early labor induction
<39 weeks’ gestation
or delivery for
suspected
macrosomia.
ELECTIVE CESAREAN
DELIVERY
• ACOG 2013, doesn’t
recommend routine
cesarean delivery in
women w/o diabetes
when fetal wt <5000g.
• In diabetics with
overgrown fetuses,
elective cesarean
delivery is tenable.

23. MANAGEMENT
“Current guidelines state that planned cesarean delivery for
diabetic pregnant woman whose fetal weight estimates
exceed 4250-4500 gm may be reasonable.”
-ACOG Practice Patterns Number 7, October 1997
“With an estimated fetal weight >4500 gm, prolonged
second stage of labor or arrest of descent in the second
stage is an indication for cesarean delivery.”
-ACOG Practice Bulletin Number 22, November 2000
“For macrosomic pregnancies including diabetic mothers,
previous deliveries with shoulder dystocia, or considering
VBAC, expectant management with vigilance for fetopelvic
disproportion will have optimal results.”
-Zamorski and Biggs, American Family Physician 2001

24. PREVENTION OF
SHOULDER DYSTOCIA
ACOG (2012) notes that fewer than 10% of all shoulder
dystocia cases result in persistent brachial plexus
injury, and 4% of these follow cesarean delivery.
Ecker and coworkers (1997) concluded that excessive
no. of unnecessary cesarean deliveries would be
needed to prevent brachial plexus injury in neonates
born to women without diabetes.
Planned cesarean delivery may be a reasonable strategy
for diabetic women with an estimated fetal weight >4250
or >4500 g.

25. SUMMARY
When fetal overgrowth is suspected, the
obstetrician naturally seeks to balance the
risks to the fetus with maternal risks.
Elective delivery for the fetus that is to be
overgrown is inadvisable, particularly <39
weeks’ gestation.
Elective cesarean delivery is not indicated
when fetal weight is <5000 g (without
diabetes) and <4500 g (with diabetes).

26. REFERENCES
• Cunningham, F. G., Leveno, K. J., Bloom, S. L., Spong, C. Y.,
Dashe, J. S., Hoffman, B. L., . . . Sheffield, J. S. (2014). Williams
obstetrics (24th edition.). New York: McGraw-Hill Education.
• Fetal Macrosomia. ACOG Practice Bulletin Clinical Management
Guidelines for Obstetrician-Gynecologists. Number 22, November
2000.
• Kingdom, J., & Smith, G. (2000). Diagnosis and Management of
IUGR. Intrauterine Growth Restriction, 257-273. doi:10.1007/978-1-
4471-0735-4_13
• Practice Bulletin No. 134. (2013). Obstetrics & Gynecology, 121(5),
1122-1133. doi:10.1097/01.aog.0000429658.85846.f9
• Zamorski MA, Biggs WS. Management of Suspected Fetal
Macrosomia. American Family Physician 2001;63:302-6.