Small for Dates Pregnancies Flashcards
a small for date baby is a baby below the _ centile in weight/abdo circumference
10th
what can cause a baby to be small?
pre-term delivery
intrauterine growth restriction (IUGR)
small parents - physiologically small
pre-term delivery is defined as delivery
37
extreme preterm is defined as a baby born between _ and _ weeks
24 and 27+6 weeks
very preterm is defined as a baby born between _ and _ weeks
28 and 31+6 weeks
moderate to late preterm is defined as a baby born between _ and _ weeks
32 and 32+6 weeks
how ocmmon is preterm delivery in the UK?
6-7%
at what gestation does survival of the foetus reach 50% likelihood?
24 1/2 weeks
causes of preterm birth?
infection over distention vascular intercurrent ilness cervical incompetence idiopathic
what illnesses during pregnancy can cause a preterm birth?
pyelonephritis
UTI
appendicitis
pneumonia
define IUGR?
failure to achieve growth potential in utero
define LBW?
birth weight <2.5kg
how is asymmetrical IUGR different from symmetrical?
the head and abdomen are not proportional eg head is big, abdomen is small
antenatal risk factors for an SGA foetus?
maternal age smoking (>11) low or high BMI low fruit intake pre-eclampsia previous birth problems co-morbidities eg HT, diabetes
1 single risk factor for SGA in pregnancy will prompt what investigations?
regular growth scanning
at what weeks gestation do you scan to check for an SGA foetus?
28
32
36
if you have 3 minor risk factors what investigations are done?
uterine artery doppler
scan at 34 weeks
what growth investigation is done in all mothers regardless of risk factors?
24 weeks
how is SGA diagnosed?
- measure foetal abdominal circumference + head circumference +/- femur length to find out estimated foetal weight
- amniotic fluid index (are they producing fluid) and doppler
what does a uterine artery doppler indicate?
checks the resistance of blood flow to the baby (should be low even in diastole as forward flow to placenta should be constant)
what maternal factors can cause an SGA baby?
lifestyle - smoking, alcohol, drugs
BMI
age
existing disease
what placental factors can cause an SGA baby?
infarcts
abruption
eg from hypertension
what foetal factors can cause an SGA baby?
infection eg rubella/CMV/toxoplasmosis
congenital anomalies eg absent kidneys
chromosomal abnormalities eg downs
if a baby is small at 24 week scan what should you consider?
this could be a chromosomal abnormality (1 in 5)
perinatal consequences of IUGR?
hypoglycaemia hypothermia polycythaemia hyperbilirubinaemia abnormal neurodevelopment
clinical features of poor growth?
reduced foetal movements
predisposing factors
fundal height below expected
reduced liquor
how is foetal wellbeing assessed in an SGA baby?
assessment of growth
cardiotocography (do this if you’re noticing clinical features)
biophysical assessment
doppler USS
what is a biophysical profile? what does it measure?
USS done for up to 20-30 mins
looks at movement, tone, foetal breathing movements, liquor volume
when would you do a biophysical profile?
if you know the baby is small and you want to see if it responds well despite this
what sign on doppler USS indicates a severe problem with the umbilical artery?
reverse end-diastolic flow (going under the line)
when would you do an MCA and ductus venosus doppler?
32-37 weeks
normal umbilical artery doppler
a positive MCA doppler increases what?
baby is shunting blood to the brain to preserve its organs
a problematic MCA doppler means flow is __
high
when would you consider earlier delivery by CS?
static growth
abnormal dopplers
if both dopplers are abnormal, when would you delivery?
between 24 and 32 weeks
if MCA doppler is abnormal but the umbilical artery doppler is fine, when would you deliver?
between 32 and 37 weeks
when would you give steroids in pregnancy
up to 36 weeks gestation (2 doses 24hrs apart) to promote survival of the baby if youre planning a preterm delivery
when would you give magnesium sulfate in pregnancy and why?
up to 32 weeks if planned preterm delivery; gives foetal neural protection
