SGA Flashcards
What is small for gestational age? Severe SGA?
Infant with birth weight < 10th centile for its gestational age
Severe < 3rd centile
What is fetal small for gestational age? Severe fetal SGA?
Estimated fetal weight or abdominal circumference < 10th centile
Severe fetal SGA < 3rd centile
What is fetal growth retriction
Pathological process has restricted genetic growth potential
Can present with features of fetal compromise such as reduced liquor volume or abnormal Doppller
What is low birth weight
<2500g
What factors can cause SGA fetus?
Normal (constitutionally) small
Placenta mediated growth restriction
Fetal factors
What are placental factors? What is the growth restriction like?
Abnormal trophoblast invasion e.g. pre-eclampsia, infarction, abruption
Maternal factors that can result in placental insufficiency:
Low pre-preganncy weight, substance abuse, autoimmune disease, renal disease, DM, HTN
Tends to cause asymmetrical growth restriction with head sparing and reduced abdominal circumference
Can result in reduced fetal kidney function resulting in oligohydramnios
What re fetal factors?
Genetic abnormalities: Trisomy 13, 18, 21 and Turner syndrome Cogenital anomalies Congenital infection - CMV, rubella Multiple pregnancy
What are major risk factors for SGA?
Maternal age > 40 Smoker Cocaine use Previous SGA baby Previous stillbirth Maternal/paternal SGA Chronic HTN DM Renal impairment Antiphospholipid syndrome Heavy antepartum bleeding Echogenic bowel - marker for trisomy 21 Pre-eclampsia Low PAPP-A (pregnancy associated plasma protein produced by placenta)
What are minor risk factors for SGA?
Maternal age >35 Nulliparity BMI < 20 IVF Pregnancy induced HTN
How is SGA diagnosed?
US
Estimated fetal weight
Abdominal circumference
Plotted on centile chars taking into account maternal characteristics, gestational age, and sex
What is the significance of head circumference to abdominal circumference ratio?
Symmetrically small fetus is more likely to be constitutionally small
Asymmetrically small fetus is more likely to be caused by placental insufficiency
Brain sparing effect can be identified by abnormal Doppler studies
What investigations in SGA?
Detailed fetal anatomical survey
Uterine artery Dopller
Karyotyping
Screen for congenital CMV, syphilis, malaria
How can SGE be prevented?
Smoking cessation
Optimise maternal disease
75mg aspirin in high risk for pre-eclampsia
When should delivery happen in SGA?
If absent/reverse end-diastolic flow on doppler delivery before 37 weeks by C-section
If abnormal uterine artery Doppler, induction of labour by 37 weeks
If normal uterine artery Doppler, induce at 37 weeks
Give maternal corticosteroids for fetal lung maturity up to 35+6 weeks
What should you consider immediately after birth
Encourage skin-to-skin contact
Ensure dry baby and kept warm
Feed within 2h of birth due to little glycogen
