19) Fetal Growth and Development

Question 1

When is the fetal period?

Answer 1

9-38 weeks

Question 2

What happens in the fetal period (generally)?

Answer 2

Growth and physiological maturation of structures created during embryonic period

Question 3

What causes rapid weight gain in later fetal period?

Answer 3

Adipose deposition

Question 4

Describe the changes to crown-rump length during development:

Answer 4

Increases rapidly in pre-embryonic, embryonic and early fetal periods, especially head
After 9 weeks, body and limb growth accelerate

Question 5

How can fetal age be assessed?

Answer 5

LMP
Developmental criteria
CRL
Biparietal diameter

Question 6

What is the normal birth weight?

Answer 6

3500g

Question 7

What birth weight would indicate a growth restriction?

Answer 7

<2500g

Question 8

What birth weight would indicate macrosomia?

Answer 8

> 4500g

Question 9

What are some causes of low birth weight?

Answer 9

Premature birth
Constitutionally small
Growth restriction

Question 10

How can fetal well-being be assessed?

Answer 10

Fetal movements
Symphysis-fundal height
Ultrasound scan

Question 11

What are the stages of lung development?

Answer 11

Pseudoglandular
Canalicular
Terminal sac

Question 12

What is the pseudoglandular stage of lung development and when does it occur?

Answer 12

8-16 weeks - terminal bronchioles form in bronchopulmonary segments

Question 13

What is the canalicular stage of lung development and when does it occur?

Answer 13

16-26 weeks - formation of respiratory bronchioles

Question 14

What is the terminal sac stage of lung development and when does it occur?

Answer 14

26 weeks to term - terminal sacs bud from resp. bronchioles and differentiation of type 1 and 2 pneumocytes

Question 15

When do breathing movements take place and why are they need?

Answer 15

12-14 weeks

Conditioning of respiratory musculature

Question 16

When is viability achieved?

Answer 16

Once lungs have entered terminal sac stage and surfactant is being produced

Question 17

Describe surfactant production in fetus:

Answer 17

Produced from around 20 weeks but significant increase after 30 weeks

Question 18

If pre-term delivery is inevitable what treatment is given and why?

Answer 18

Glucocorticoids to mother which drives surfactant production in fetus

Question 19

When is definitive fetal heart rate achieved?

Answer 19

15 weeks

Question 20

When does fetal kidney function begin?

Answer 20

10 weeks

Question 21

What cause oligohydraminos?

Answer 21

Placental insufficiency, fetal renal impairment

Question 22

What causes polyhydraminos?

Answer 22

Fetal abnormality e.g. inability to swallow

Idiopathic

Question 23

Why does infant mobility increase in the first year?

Answer 23

Corticospinal tract myelination incomplete at birth

Question 24

When do fetal movements start and when are they felt by mother?

Answer 24

8th week, felt at 17 weeks