Foetal growth Flashcards
What 2 main groups of factors influence foetal growth?
Intrinsic - genetic (cannot do anything about)
Extrinsic - environmental
What is the difference between miscarriage and stilllbirth?
up to 24 weeks: miscarriage
after 24 weeks: still-birth
Why is foetal growth important?
Can indicate risk of still birth
What are some maternal extrinsic factors effecting foetal growth?
social class (smaller babies, higher risk of still born)
nutritional status
environment: altitude
pre-existing disease: cardiac/renal/respiratory/vascular
pregnancy-related disease:
hypertension (small babies), diabetes (big babies)
What are some foetal extrinsic factors effecting foetal growth?
nutrition: placental
teratogenic: tobacco, narcotics, alcohol, medication
infective: - viral: rubella (small babies), CMV (small babies) (V-Z, measles, hepatitis A and B) - protozoan : toxoplasma (small babies) - others: listeria, syphilis
What are some intrinsic factors effecting foetal growth?
Maternal:
height and weight
parity (more pregnancies = bigger babies)
ethnic group
Fetal:
sex
genes/inherited conditions
What happens if a midwife thinks the baby is small?
Midwife will refer mother to obstetrician
What things would you ask a mother who has reduced foetal growth?
Hx of small babies
Medical conditions Medicines Smoking, alcohol nutrition general fitness etc.
Foetal movements (from about 26 weeks)
How would you examine a woman who has reduced foetal growth?
General assessment
Obstetric examination: fundal height
liquor volume
What is SGA?
small for gestational age:
Foetus that has failed to achieve a specific biometric or estimated weight threshold by a specific gestational age
What small babies would you not be worried about?
Constitutionally small babies
What would you be concerned about in a small baby that is not just constitutionally small?
intra-uterine growth restriction
How do you measure the growth of a baby?
BPD: biparietal diameter
HC: head circumference - plot on graph to see whether this is normal or not
AC: abdo circumference
FL: femur length
After how long are growth scans usually repeated if IUGR is suspected?
2 weeks
If a baby has IUGR, what does their AC graph usually look like?
plateau, rather than curve
If a baby has a normal HC, but small AC, what is this called? What does this indicate?
Head-sparing effect - more blood goes to head, therefore abdo and chest do not grow as well
IUGR
What are we worried about in IUGR?
placenta will shut down
What is another name for a growth scan?
foetal assessment scan
Other than measuring the baby, what else is done in a foetal assessment scan? What are other ways people might assess foetal development?
BPP: biophysical profile
- fetal breathing movements
- fetal movements
- fetal tone
- amniotic fluid volume (reduced because less blood to baby’s kidneys, therefore reduce urine output)
ASK WHAT THE MOTHER THINKS IS HAPPENING RE. MOVEMENT
Kick charts
Heart rate monitoring (CTG)
Assess baby’s feeding (placental assessment): Doppler studies
How do we assess the placenta in foetal assessment?
umbilical and uterine flow doppler studies:
appearance
blood flow characteristics
foetus to placenta: umbilical
mother to placenta: uterine
What are the important readings taken from doppler study?
Pulsatility index and resistance index
What does a progressively greater resistance index found on a doppler scan lead to?
absent or reversed EDF
What should be shown on a umbilical Doppler ultrasound?
Blood flow should take place during systole and diastole.
If there isn’t (or worse, LOSS of blood) = VERY WORRYING
What are the two main causes of SGA babies?
Constitutionally small
IUGR
