foetal growth

Question 1

foetal growth ie length vs and weight during pregnancy

Answer 1

most rapid at start, then length slowly plateaus, whereas fetal weight rises slowly at start, and becomes more rapid

Question 2

3 phases of foetal growth

Answer 2

hyperplasia, then hyperplasia+ hypertrophy in 2nd trimester, then only hypertrophy in 3rd, thus hypertrophy key for fetal weight

Question 3

SPH (symphysis fundal height) technique- purpose+ pros and cons

Answer 3

measure distance in abdominal wall between pubic symphysis and top of uterus to determine age of baby- it’s simple, but low detection rate+ affected by other factors eg mother BMI

Question 4

what measure used to date pregnancies d, and what when after 14 weeks

Answer 4

by crown rump length ie top to bottom, or head circumferance if first scan AFTER 14 weeks

Question 5

how ultrasound assesses foetal growth

Answer 5

measure biparietal diameter, head circumference, abdominal circumferance and femur length, and combine to form foetal weight, and then do this multiple times and plot on a foetal growth chart

Question 6

maternal and fetoplacental factors affecting foetal growth

Answer 6

diet, alcohol, smoking, disease eg diabets, mothers age- fetoplacental factors include gender (males bigger), and hormons

Question 7

customised growth chart

Answer 7

adjusted for maternal height/weight+ ethnicity

Question 8

why ultrasound used

Answer 8

doesn’t just assess size, but also it’s wellness ie whether moving, whether it’s metabolically compromised- can also look at trends in growth, and whether baby needs to be delivered prematurely

Question 9

define small for gestational age

Answer 9

birth weight below 10%

Question 10

foetal growth restriction- define and danger

Answer 10

fetus doesn’t achieve its predetermined growth potential- most common cause for stillborn babies

Question 11

determiants of early growth restriction

Answer 11

measure size, and umbilical doppler (blood flow)

Question 12

effects of low birth weight/FGR

Answer 12

respiratory issues, sepsis, hypoglycaemia, developmental delay

Question 13

causes of small for gestational age

Answer 13

may be foetal issue (eg abnormality/infection) or problem with placenta (eg pre-eclampsia- spiral arteries stay narrow), or could simply be dating issue

Question 14

pre-eclampsia and cause

Answer 14

maternal hypertension (above 140) with proteinuria (above 0.3g) due to less remodelling of spiral arteries

Question 15

when foetuses need monitoring

Answer 15

mum had previous maternal hypertension/FGR/stilll birth, and if there is abnormal PAPP-A in blood (above 0.3)

Question 16

uteroplacental doppler screening

Answer 16

assesses uterine arteries ie whether there is high resistance- positive increases risk of pre-eclampsia ie FGR

Question 17

sequence of events in blood vessels- uterine, umbilical, middle cerebral, ductus venosus

Answer 17

uterine arteries affected first, then umbilical arteries- babies then have increased flow to brain due to hypoxia (via middle cerebral artery), but less to lungs and kidneys (less to kidneys= less amniotic fluid): then less blood in ductus venosus, suggesting baby needs to be delivered soon

Question 18

importance of CTG and foetal movement

Answer 18

if they are moving, indicating there is no hypoxia, so they will move, and heart rate (CTG) is normal

Question 19

when FGR pregnancies delivered

Answer 19

above 28 weeks/above 500 g

Question 20

early vs late growth restriction

Answer 20

early is rarer and more correlated to pre-eclampsia ie maternal disease: difficult to manage, whereas late is more common, less correlated to pre-eclampsia, and easy to manage (simply deliver)

Question 21

what is low birth weight and significance

Answer 21

less than 2.5kg-

Question 22

difference between low birthweight because born preterm and low birth weight because growth restricted

Answer 22

if you are growth restricted ie 2.5kg at term, means you are more vulnerable to abnormalities: if you are 2.5kg simply because you are born preterm, thats fine

Question 23

sensitivity vs specificity when choosing centile

Answer 23

when choosing what centile to use for determining growth restriction, 10% most sensitive, but 3% most specific ie get false negatives ie some restricted babies might be misssed

Question 24

when does growth restriction occur

Answer 24

mainly in 2nd/3rd, weight gain occurs mainly then

Question 25

treating IUGR+ pre-eclampsia

Answer 25

corticosteroids eg for lungs