7. Foetal growth and dev.

Question 1

during which period is there the greatest growth and weight gain

Answer 1

During foetal period - week 9 to term

Question 2

what are the 2 main goals of the foetal period

Answer 2

1. growth and physiological maturation of the structures created during the embryonic period
2. preparation for transition to independent life after birth

Question 3

how do foetal body proportions change during foetal period

Answer 3

CRL increases rapidly through pregnancy but body proportions change dramatically during foetal period:

• week 9: head = 1/2 CRL…
• trunk and limb growth accelerates…
• week 38: head = 1/4 CRL

Question 4

how does weight gain change during foetal period

Answer 4

Slow at first then increases rapidly in mid- and late foetal periods:

• early foetus: protein deposition for muscle growth
• late foetus: adipose deposition for nutritional support and thermoregulation post-delivery

Question 5

name 5 hormones required for foetal growth

Answer 5

1. insulin
2. IGF-II: nutrient-independent, dominant in T1
3. IGF-I: nutrient-dependent, dominant in T2 and 3
4. leptin (placental production)
5. EGF and TGFa

Question 6

what are the dominant cellular growth mechanisms during pregnancy

Answer 6

i) 0-20 wks: hyperplasia
ii) 20-28 wks: hyperplasia + hypertrophy
iii) 28-38 wks: hypertrophy

Question 7

what are the effects of maternal malnutrition on foetal growth early and late in pregnancy

Answer 7

can cause growth restriction:

• symmetrical (proportionally small, inc. organs): associated with early growth restriction
• asymmetrical (head-sparing, abdominal growth restriction): associated with later growth restriction when head has already developed

Question 8

why are folic acid dietary supplements recommended during pregnancy

Answer 8

• required for DNA synthesis/cell division and as substrate for many enzymatic reactions
• essential for dev. of nervous system - deficiency can result in NEURAL TUBE DEFECTS such as SPINA BIFIDA

Question 9

how can maternal perceptions be used to assess foetal well being

Answer 9

• should be able to detect foetal movements from at least 20 wks
• can monitor changes in sleep patterns etc

Question 10

why are measurements of uterine expansion regularly performed and what is this called

Answer 10

symphysis-fundal height: approx. measurement of foetal size, although distorted by diff. volumes of amniotic fluid

Question 11

why is an ultrasound scan routinely carried out at 20wks

Answer 11

To assess foetal growth and detect any anomalies - all organ systems should be developed and large enough to see by then but still early enough for TOP

Question 12

why are doppler US sometimes used to assess pregnancy

Answer 12

used to measure blood flow and direction at the placenta to investigate uteroplacental and foetoplacental circulations - can cause foetal growth restriction if compromised

Question 13

describe 3 different mechanisms for estimating foetal age

Answer 13

1- date of LMP: prone to inaccuracy (irregular cycles in some women)
2- developmental criteria: allow accurate estimation:
- Crown-rump length (CRL) - measured between wks 7-13 (correlation less accurate later in pregnancy)
- Bi-parietal diameter - distance between parietal bones of foetal skull, used in combination with abdominal circumference and femur length to date pregnancies in T2 and T3

Question 14

what is macrosomia and when does it often occur

Answer 14

baby >4.5 kg, suggests gestational diabetes