Placenta and trophoblasts II

Question 1

Define foetal growth restriction (FGR)

Answer 1

Notoriously difficult to define
• Definition is conceptual
• Is a condition in which the foetus does not reach its
biological growth potential
• Often equated to being small
• Not all small foetuses are growth restricted
• Not all growth restricted foetuses are small

Question 2

How to measure FGR

Answer 2

Growth involves increment in a
time interval
• Usual method is to plot fetal size
against gestation
• Various centile cut-offs are used
for diagnosis of SGA
Graph can show if the foetus is too large or too small for gestational age

Question 3

What are the causes of smallness in a foetus

Answer 3

Dating problems
• Constitutional
• Primary fetal/environmental
problem
• Placental insufficiency

Question 4

Chromosomal/genetic reasons for smallness (name conditions)

Answer 4

Chromosomal abnormalities
(e.g. Trisomy 18, Triploidy)

• Congenital infections
(e.g. Rubella, CMV)

• Genetic syndromes
(e.g. Russell-Silver syndrome)

• Teratogens
(e.g. Fetal alcohol syndrome, Drug abuse)

• Maternal problem
(e.g. Cyanotic CHD)

Question 5

Describe one of the reasons for a foetus being too small: placental insufficiency

Answer 5

Placenta function is nutrient and gas
exchange
• Poor function will lead to:
• Slowing of growth
• Hypoxaemia – Hypoxia – Asphyxia
• Stillbirth
• Ultrasound used to find evidence of
• Placental dysfunction
• Fetal response to the dysfunction

Question 6

Potential reasons why placental insufficiency could be a problem (who does it affect)?

Answer 6

Risk factor- eg maternal age, smoking, drug misuse
• Previous history- eg. previous still birth or maternal issues such as diabetes, chronic hypertension, previous still birth
• Positive uterine arterial Doppler screen
• Abnormal placental echo-texture
• AC below the 5th centile