Small Babies Flashcards by Munaam Fatima

Embryonic period is characterised by

Intense organogenetic activity
Growth is very little except for the placenta

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When is there an acceleration in growth of the foetus

After 8 weeks

Leads to exponential increase in weight of foetus

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What is an accurate measure of assessing the age of the embryo

Crown rump length CRL

At 9 weeks = 5cm

At 38 weeks = 36cm

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Weight gain in the early foetal stage is due to _____

Deposition of new protein

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Weight gain in the late foetus stage is due to

Deposition of adipose tissue

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How do body proportions change as the foetus grows

At week 9 the head and neck account for half of the length of the foetus

As foetus grows (limbs and trunk) = more proportionate

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What is main mechanism of growth in the first 20 weeks

Hyperplasia

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What is the mechanism of growth in 20-28 weeks

Hyperplasia and hypertrophy

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What is the mechanism of growth after 28 weeks

Hypertrophy

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Growth restriction can be……

Symmetrical = proportional growth of the head and body

Asymmetrical = head is spared and body is disproportionately smaller

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Hormones that are essential for foetal growth

Insulin

IGFII = nutrient independent in dominates in T1

IGF I - nutrient dependent and dominates in T2 and T3

Leptin = important in placental formation

Epidermal growth factor EGF and TGF alpha (transforming growth factor)

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Which hormone is nutrient independent and what trimester does it dominate

Insulin like growth hormone I

Trimester 1

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What is macrosomia

Baby weight greater than 4.5kg

Indicative of gestational diabetes

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What is considered a healthy weight for a newborn

3.5kg

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Less than ________kg is suggestive of foetal growth restriction

2.5kg

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Why can babies have a low birth weight

if are born prematurely
smaller mothers give birth to smaller babies
if have suffered growth restriction

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There is a greater risk of ________________ & ________________ in IUGR babies

Mortality
Morbidity

What things can be looked at in an antenatal assessment of foetal wellbeing

mother ( fetal movements or not)
biochemical tests
regular measurement of uterine expansion by measuring symphysis-fundal height
ultrasound scan

What are we trying to detect in a biochemical test

hCG maintains corpus luteum
HPL (human placental lactogen) regulates metabolism of macromolecules
alpha fetoprotein - transfer of heavy metal ions in to the foetal bloodstream

What are the negatives of biochemical tests

Expensive

Poor positive predictive value

A 12 week scan is carried out for what reasons

Rule out ectopic pregnancies
Number of foetuses?

A 20 week scan is carried out for what reasons

Assess foetal growth and any anomalies

What is used between 7-13 weeks

Crown rump length

To date the pregnancy, estimate EDD

Head and abdominal circumference with femur length is measured at ______

20 weeks

What is a Doppler ultrasound used for

Assessment of wave pattern of blood through umbilical artery Used in assessment of IUGR at risk babies

What is the Normal results of a Doppler ultrasound

Increase in diastolic velocity There will be a decrease in the indices measured such as PSV, MDV and TAPV PSV = peak systolic velocity MDV = mean diastolic velocity TAPV = time averaged peak velocity

Worsening umbilical artery Doppler shows

1) increased systolic: diastolic ratio with no rise in diastolic flow 2) absent end diastolic flow in the umbilical artery 3) reverse diastolic flow - there is reflux through the artery

What are features are indicative of early foetal hypoxia

Raised umbilical artery pulsatility Absent end diastolic flow

What other artery can a Doppler look at

Uterine artery

What is the pathogenesis of IUGR

Normally to establish a high flow, low resistance system remodelling of the spiral arteries is required. Remodelling is carried out by invading trophoblasts which migrate into the arterioles and replace the endothelial cells with trophoblast cells Reduction/loss of vascular smooth muscle in spiral arteries so cannot spasm and create high flow, low resistance flow that is needed

What is the decidual reaction

Endometrium becomes the decidua Reaction creates Goldilocks zone - enough invasion to allow permissive circulation but not too much that it invades the myometrium as well

A sub-optimal decidual reaction can lead to what kind of adverse effects in pregnancy

Placental insufficiency Pre-eclampsia

What are foetal risk factors for IUGR

Genetics: chromosomal abnormalities or single gene disorders Epigenetics = methylation disorder Infections = TORCH

What infections can increase a foetuses risk for IUGR

TORCH Toxoplasmosis Others varicella, syphilis and parvovirus Rubella Cytomegalovirus HIV

What maternal risk factors are there for IUGR

Pre-existing medical conditions such as chronic hypertension, renal disease and CVD Drug exposure = smoking and alcohol

Which placental factors pose a risk for IUGR

Placental infarction Placental abruption = placenta torn away from decidua Placental insufficiency = hypertensive disorders and maternal diabetes

Why does timing of the insult matter

Early phase insult = hyperplasia phase in which foetus is symmetrically affected in terms of IUGR Late phase insult = hypertrophy phase where foetus is asymmetrically affected

How is the head sparing effect achieved

Decreased glycogen deposition in the liver Decreased adipose tissue deposition in the system = decreased abdominal size in proportion to body

What is the barker hypothesis

Foetal programming during development leading to adult metabolic disorders Obesity, diabetes, insulin insensitivity, hypertension, hyperlipidemia and CHD

A sub-optimal in utero environment may impact adult health how

Pulmonary insufficiency Hypertension Renal insufficiency Insulin insufficiency Altered glucose/lipid metabolism Immune deficiency Neurodegenerative and cognitive diseases Obesity