S7.2 Foetal Growth & Development

Question 1

Define the foetal period

Answer 1

End of W8-term, where growth and physiological maturation of the structures created during the embryonic period occur.

Pre-embryonic period is 1-3 weeks, embryonic 3-8 weeks and foetal 8-38 weeks.

Question 2

What type of cell growth occurs in week 0-20?

Answer 2

Hyperplasia

Question 3

What type of cell growth occurs in week 20-28?

Answer 3

Mix of hyperplasia and hypertrophy

Question 4

What type of cell growth occurs in week 28-38?

Answer 4

Hypertrophy

Question 5

Describe the crown rump length at week 9

Answer 5

At W9 the head is half of the CRL but after this the body lengthens and limbs grow more.

Question 6

Describe some techniques used to assess foetal development

Answer 6

Amniocentesis: sample amniotic fluid for foetal cells to diagnose conditions, can use karyotyping.

Foetal movements: assessed by the mother

Symphysis-fundal height: distance in cm from pubic symphysis to fundus of uterus. Lag of >4cm indicates foetal growth restriction.

Question 7

How can USS be used to asses foetal development?

Answer 7

Can predict weight, appearance, number, age, rule out ectopics.

Measurements include CRL (in T1 for dating of pregnancy).
Biparietal diameter (distance between the parietal bones, used to date in T2 and 3), abdominal circumference and femur length

Question 8

Why is USS carried out around week 20?

Answer 8

This is when everything in the foetus has developed large enough to see.

Question 10

Describe surfactant production

Answer 10

TII pneumocytes start making surfactant around W20 but not significantly increased until W30, foetus not viable before 24 weeks because of this reason

Question 11

What is respiratory distress syndrome?

Answer 11

Lack of surfactant in premature babies, surface tension higher, inspiration more difficult.
If pre-term delivery is known in advance can give steroids to increase foetal surfactant.

Question 12

Describe the development of the foetal respiratory system

Answer 12

Embryo develops the bronchopulmoanry tree.
W4 - tracheoesophogeal septum formed
W8-16 (pseudoglandular stage) - bronchioles form
W16-26 (canalicular stage) - respiratory bronchioles form
W26-term (terminal sac stage) - terminal sacs form and T1+2 pneumocytes differentiate and produce surfactant
Birth-8y - alveoli form

Question 15

Describe the development of the foetal CVS

Answer 15

Foetal heart rate achieved at week 15

Question 16

Describe the development of the foetal urinary system

Answer 16

Kidney function beings in week 10.

Without this can get oligohydramnios (too little AF) or polyhydramnios (too much AF)

Question 17

Describe the development of the foetal nervous system

Answer 17

Week 16 - corticospinal tracts begin to form

Week 36 - Brain myelination begins