fetal growth disorders Flashcards
which measurements are used for the estimation of fetal weight ?
BPD biparietal diameter HC head circumference AC abdominal circumference FL femur length all by ultrasound
what is fetal growth rate affected by ?
placental function
genetic or constitutional factors
what factors affect fetal birth weight ?
function of both gestational age rate of fetal growth
what does appropriate for gestational weight mean ?
infants born with a birth weight between 10th and 90th centile for their gestational age
what does small for gestational age mean ?
infants born with a birth weight less than 10th centile for their gestational age
what does large for gestational age mean ?
infants born with a birth weight more than 90th centile for their gestational age
what does fetal growth restriction mean ?
implies a pathological restriction of the genetic growth potential and they may show signs of fetal compromise
what does low birth weight mean ?
infants with a birth weight less than 2500 g regardless of their gestational age
when do we consider a baby to be born pre-term?
24 to 36 weeks
when do we consider a baby to born early term ?
37-38 weeks
when do we consider a baby to be born full term ?
39-40 weeks
when do we consider a baby to be born late term ?
41 weeks
when do we consider a baby to be born post term ?
at 42 weeks
what can we divide babies that are born small for gestational age into ?
normal/constitutional
non placenta mediated growth restriction
placenta mediated growth restriction
how do we screen for SGA ?
history biochemical markers (PAPP-A) uterine artery doppler at 20-24 weeks gestation ( anomaly scan) clinical examination
how do we make a diagnosis of SGA ?
ultrasound biometry
doppler
amniotic fluid index
what is the brain sparing syndrome ?
in cases of chronic placental insufficiency the fetus reacts to the restricted placental perfusion by redirecting the blood back to the brain
what are the results of the brain sparing syndrome ?
- an increased ( head circumference/ abdominal circumference ratio )
- reduced renal perfusion and decreased urine output which causes oligohydraminous
what can be done to prevent SGA ?
- anti-platelete agents may be effective
2. cessation of smoking
when should anti-platelete agents be commenced ?
should be commenced at or before 16 weeks of pregnancy
what is the primary surveillance tool in the SGA ?
umbilical artery doppler
what other blood vessels are important to asses using doppler ?
middle cerebral artery
ductus venous
other than doppler what can be used for fetal surveillance in SGA ?
CTG
US assessment of amniotic fluid volume
biophysical profile
what are the aspects of the biophysical profile ?
- breathing movement
- gross body movement
- tone
- amniotic fluid volume
what is the management in SGA ?
if planning to deliver between week 24 and week 35 weeks :
give antenatal corticosteroids
offer Magnesium Sulphate
what is the management if the baby with SGA has a normal umbilical artery doppler ?
delivery should be offered at 37 weeks with doppler follow up every 14 days
what is the management if the baby with SGA has an abnormal umbilical arttery doppler ?
this depends on if the end diastolic velocities are preserved :
- if they are —> deliver no later than 37 weeks with doppler follow up twice weekly
- not preserved —> delivery should be considered between 30-32 weeks with daily follow up with doppler
how should an SGA baby be delivered ?
if the end diastolic velocities are perserved then normal labour can be offered
for no perserved end diastolic velocity caesarian section should be offered
when can we call a fetus macrosomic?
when the fetus is born exceeding 4000 gm regardless of its gestational age
what are the risk factors for having a macrosomic baby ?
maternal diabetes maternal obesity post-term pregnancy grand multipara previous LGA baby
what are the fetal complications of macrosomia ?
IUFD
birth trauma
hypoglycemia
what are the maternal complications of macrosomia ?
higher chance of CS delivery
trauma to the birth canal
postpartum hge
when do we plan for an elective CS in macrosomic babies ?
5 kg baby in non diabetic women
4.5kg in diabetic women
