Fetal Growth Restriction

Question 1

Discuss the causes of a small fetus

Question 2

Define the cocept of FGR

Question 3

Pathophysiology of poor placentation using Doppler assessment

Question 4

Methods of detecting FGR

Question 5

Diagnotic and management differences

Question 6

FGR

Answer 6

Notoriusly difficult to define
Definition is conceptual
Is a condition in which the fetus does not reach its biological growth potential
Often equated to being small
Not all small fetuses are growth restricted
Not all small fetuses are growth restricted
Not all growth restricted fetuses are small

Question 7

Growth vs Size

Answer 7

Growth involves increment in a time interval
Usual method is to plot fetal size against gestationos

Question 8

Causes of smallness

Answer 8

Dating problems
Constitutional
Primary fetal/ environmental problem
Placental insufficiency

Question 9

Smallness: Fetal/Environmental

Answer 9

ROCK BOTTOM FEET
Inefection (HPV) causing deformities

Question 10

Smallness: Fetal/Environmental

Answer 10

Chromosomal conditions
Congenital infections
Genetic syndromes
Teratogens
Maternal problem (Cyano

Question 11

Placental insufficiency

Answer 11

Placenta function is nutrient and gas exchange
Poor function will lead:
- slowing growth
- hypoxemia-> hypoxia–> asyphyxia

Question 12

Placentall insufficency: clinical setting

Answer 12

Risk factor
- maternal age >40years
- ongoing smoker (at booking)
- drug misuse
previous history
positive uterine artery doppler screen
abnormal placental echo-texture
AC/EFW below the 3rd centile

SMOKING: lesser chance of eclampsia

Question 13

Foetal-maternal circulation

Answer 13

Umbilical arteries have deoxygenated blood and travel to placenta
Umbilical vein has oxygenated blood
Ductus venosus shunts the blood through the foramen ovale straight into the left side of the heart and then systemic circulation- first goes to head + neck via carotid, so goes up to brain
Then goes back down descending aorta and back to placental arteries
Doppler looks at placental function + foetal response
Test placental function on maternal and foetal side
Maternal = uterine arteries
Foetal = umbilical arteries- want a low resistance for good perfusion
Consider foetal response too:
Foetal = middle cerebral artery (want high resistance as low resistance means there’s a lack of oxygen), ductus venosus (backflow means there’s no perfusion)

Important things to consider;
Uterines- maternal side of placental function
Umbilical arteries- foetal side of placental function
Foetal response to any hypoxia
Middle cerebral artery- is it compensating?
Is baby decompensating w abnormal ductus venosus?

Question 14

Redistribution

Answer 14

In case of baby having hypoxia, there will be shunt to the brain (can be detected)

Question 15

(PLACENTAL FUNCTION- LOOK AT BABy’S RESPONSE TO IT)

Answer 15

Uterine arteries is maternal
Umbilical arteries is foetal

High resistance in in the heart= high resistance in the uterine areries

Question 16

dopper flow

Answer 16

Doppler flow basics
Peak = systole, trough = diastole
Big, wide troughs = good as lots of blood returning to placenta = good perfusion, low resistance
Always want forward flow
Reversed flow = backflow, so no gas exchange
Doppler changes in FGR
Low resistance to brain = poor blood flow

Question 17

Pregnancy Doppler Assessment

Answer 17

Methods for detecting FGR
Clinical: symphysis-fundal height (not v reliable)
Serial US biometry
Uterine artery Doppler screening
Preterm FGR (<37 weeks)
Diagnosis, foetal response + monitoring is well characterised
Pathophysiology + natural history is understood
Preterm FGR Doppler changes
Umbilical artery resistance increases
MCA resistance lowers = baby is redistributing
Abnormal ductus venosus (+ baby moves less to conserve energy)
Abnormal foetal heart rate

Question 18

Monitory-umbilical artery

Answer 18

Monitoring-umbilical artery
Umbilical artery (UA) Doppler has proven beneficial
Reduces the risk of perinatal deaths + may result in fewer obstetric interventions

Question 19

FGR 28-36 weeks

Answer 19

Increased PI in UA is abnormal
Deliver for reversed EDF at 32 weeks
Deliver for absent EDF at 34 weeks
Deliver for PI >95th at 37 weeks
** MCA Dopplers not needed (less than 37 weeks) if UA Dopplers are normal

Question 20

Truffle delivery criteria

Answer 20

TRUFFLE delivery criteria
Use this criteria to monitor small babies (<32 weeks) to decide when to deliver them
So: Measure BF to ductus venosus + do heart tracing + then figure out when to give birth
cCTG = STV <3.5mmsecs (<29w) or STV <4msecs (>29w) on 2 occasions on the same day
If STV > 4 = everything’s okay, keep being pregnant + no need to deliver yet
Early DV = abnormal DV PI (on 2 occasions on the same day)
High resistance but normal forward flow
Late DV = DV a-wave absent/reversed (on 2 occasions on the same day)- had better intact survival rate at 2 years

Question 21

FGR>37 WEEKS

Answer 21

FGR >37 weeks
Increased PI in umbilical artery is abnormal = deliver
Normal umbilical artery PI alone is not enough
MCA Dopplers needed even if umbilical artery Dopplers are normal
Deliver if MCA PI < 5th centile
At EFW <3rd centile, deliver at 37 weeks
At EFW 3rd-10th centile, deliver at 39 weeks

Question 22

Serious perinatal complications

Answer 22

Serious perinatal complications
Stillbirth
Cerebral palsy/disability
IVH/convulsions
HIE grade 2/3
Neonatal convulsions
Treatment options?
Sildenafil might improve foetal growth in utero by vasodilation
But actually deemed detrimental long term

Question 23

What is FGR?

Answer 23

FGR = condition in which the foetus does not reach its biological growth potential
Growth involves increment in a time interval- usual method is to plot foetal size against gestation
Various centile cut offs are used for diagnose of SGA (small for gestational age)

Question 24

Causes of Smallness

Answer 24

Causes of smallness: dating problems, constitutional, primary foetal/environment problem, placental insufficiency
Foetal/environmental:
Chromosomal conditions- trisomy 18, triploidy (test via placental biopsy- chorionic villus sample)
In triploidy, baby has big head + placenta tends to be extra big + v vascular, so produces v high hCG levels
High hCG = mother v sick as hCG stimulates vomiting centres
Congenital infections- rubella, CMV
CMV = ventriculomegaly (periventricular shadowing + enlarged ventricles)
Take sample of amniotic fluid + test for CMV
Genetic syndromes- Russell-Silver syndrome
Characterised by poor growth + reduced intellectual activity + low set ears
Teratogens- foetal alcohol syndrome, drug abuse
Maternal problem- cyanotic CHD
If mother is cyanotic, baby will also lack oxygen

Question 25

Methods of detecting FGR

Answer 25

Clinical: Symphysis-fundamental height
Serial ultasound biometry
Uterine-artery Doppler screening

Question 26

Placental insufficiency

Answer 26

Placenta function = gas exchange and nutrition
Poor function leads to: slowing of growth and eventually metabolism, hypoxemia -> hypoxia -> asphyxia, still birth
Ultrasound used to find evidence of: placental dysfunction + foetal response to the dysfunction
Clinical setting
Risk factor
Previous history
Positive uterine artery Doppler screen
Abnormal placental echo-texture
AC/EFW below the 3rd centile

Question 27

Placenta mediated FGR- definitions

Answer 27

Placenta mediated FGR- definitions
Early FGR: GA <32 weeks in absence of congenital anomalies
AC/EFW < 3rd centile or UA-AEDF
OR AC/EFW < 10th centile combined w:
UtA-PI > 95th centile and/or:
UA-PI > 95th centile
Late FGR: GA > 32 weeks, in absence of congenital anomalies
AC/EFW < 3rd centile
OR at least 2 out of 3 of the following:
AC/EFW < 10th centile
AC/EFW crossing centiles > 2 quartiles on growth centiles
CPR < 5th centile or UA-PI > 95th centile
What stuff means:
GA = gestational age
AC = abdominal circumference
EFW = estimated foetal weight
UtA-PI = uterine artery pulsatility index
UA-PI = umbilical artery pulsatility index
CPR = cerebroplacental ratio

Question 28

Symphysis Fundal Height

Answer 28

One trial with 1639 women was available
Antenatal detection of