Small for dates Flashcards
Pre-term delivery
deliver <37 weeks gestation
extreme pre-term
24 - 27+6 weeks
very pre-term
28 - 31+6 weeks
moderate to late pre-term
32 - 36+6 weeks
list some risk factors for pre-term birth.
previous PTL multiple uterine anomalies teenager parity (=0 or >5) ethnicity poor socioeconomic status smoking drugs esp. cocaine BMI <20
What constitutes a small for gestational age (SGA) foetus?
estimated foetal weight or abdominal circumference <10th centile
Failure to achieve growth potential (IUGR/FGR)
Birth weight <2.5kg (regardless of gestation)
What is growth restriction divided into? Describe each category.
Symmetrical and asymmetrical.
Symmetrical = small head and body.
Asymmetrical = normal head, small body.
What might cause symmetrical growth restriction?
chromosome abnormality, intrauterine infection, environmental condition.
What might cause an asymmetrical growth restriction?
placental reasons - baby is diverting blood to head to protect brain growth over other less vital organs.
smoking
Describe the level of monitoring for a woman with major antenatal risk factors for an SGA baby.
A single major risk factor means that foetal size will be measured at 26/28 weeks and then regularly until birth.
“serial growth scans” = minimum 28, 32 and 36 weeks
Minor antenatal risk factors for SGA foetus.
maternal age >/= 35 IVF pregnancy nulliparity BMI <20 1-10 cigarettes/day low fruit pre-pregnancy previous pre-eclampsia pregnancy interval <6 months pregnancy interval >60 months
How many minor antenatal risk factors are needed to require a growth scan at 34 weeks?
3 minor risk factors
Major antenatal risk factors for SGA foetus.
maternal age >40 smoker >= 11 /day paternal/maternal SGA cocaine use daily vigorous exercise previous SGA baby previous stillbirth chronic hypertension diabetes with vascular disease renal impairment anti-phospholipid syndrome heavy bleeding in pregnancy low PAPP-A BMI >35 known large fibroids
What measurement do all pregnant women get?
symphyseal-fundal height from 24 weeks
What is needed to diagnose SGA?
measure foetal abdominal circumference
combine with head circumference ± femur length to give EFW
What additional information can help diagnose SGA?
liquor volume or amniotic fluid index and Dopplers
What is the minimum to consider when looking at customised growth charts?
maternal parity
BMI
ethnicity
When do women in Tayside have uterine artery doppler’s performed? What is expected to be seen?
performed as part of 20 week scan
pregnancy should be a low resistance state - uterine arteries should become low resistance vessels in 2nd trimester with forward flow to the placenta even in diastole.
What abnormality might you see on uterine artery doppler and what is mother at risk of?
if resistance is seen in both uterine arteries the woman is at risk of SGA and hypertensive disease in pregnancy.
What are some clinical features of poor foetal growth?
(predisposing factors)
fundal height < than expected
reduced liquor
reduced foetal movements
When assessing a foetus using its biophysical profile - what is being looked for?
movement
tone
foetal breathing movements
liquor volume
score out of 10: 8-10 fine; 4-6 repeat; 0-2 deliver.
What does ductus venous allow?
key in foetal circulation to allow shunting of oxygenated blood to by-pass the liver and move via IVC to oxygenate the brain
What are the indications for considering earlier delivery by C/S?
growth becomes static
abnormal uterine artery doppler
normal umbilical artery doppler with abnormal MCA between 31-37 weeks
abnormal umbilical artery doppler with abnormal ductus venous doppler at 24-32 weeks.
what two drugs are given if planning early delivery?
steroids and magnesium sulphate
