IUGR/SGA

Question 1

SGA - definition

Answer 1

EFW on U/S

Question 2

IUGR - definition

Answer 2

SGA (?) fetus that is failing to reach its true growth potential

Question 3

Types of SGA

Answer 3

1. Normal small - following along its own centile, which is where it is genetically or ethnically meant to be; U/S shows a structurally normal symmetrically small fetus, amniotic fluid and dopplers
2. Incorrectly diagnosed small - bc dates are wrong. Fetus is simply earlier in gestation than anticipated (LMP uncertain - e.g. conception following OCP use, or after breastfeeding, or no early U/S to confirm dates in pregnancy). U/S shows a symmetrically small biophysically well fetus that grows along its centile
3. Symmetrical IUGR (tends to present earlier than asymmetrical IUGR)
   - Chromosomal abnormality (triploidy, trisomy 13, trisomy 18)
   - Infections (e.g. TORCH)
   - External agents (e.g. nicotine, alcohol)
4. Asymmetrical IUGR (tends to present later than symmetrical IUGR - typically in 3rd trimester)
   - Placental insufficiency (most common cause)
   - Pre-eclampsia

Question 4

IUGR - complications

Answer 4

1. Perinatal mortality (6-10x)
2. Cerebral palsy (4x)
3. Meconium aspiration
4. Emergency CS
5. Necrotising enterocolitis

(Also - hypoglycaemia, hypcalcaemia, intrapartum fetal distress and asphyxia)

Question 5

IUGR - mx

Answer 5

1. Early identification and intensive fetal monitoring. Aim = continue the pregnancy safely for as long as possible but deliver before the fetus becomes excessively compromised
2. Assign risk - find normal babies developing in abnormal situation (ultrasound biometry, amniotic fluid volume, umbilical cord doppler). Continue with regular antenatal check ups + extra screening. If baby is high risk, repeat U/S + doppler in 2-4 weeks
3. Preterm babies should only be delivered if they show signs of distress, ensuring maximum maturity while avoiding any harm. Give steroids (betamethasone 12mg IM), monitor using umbilical cord doppler, deliver if reversed diastolic flow in umbilical cord or if CTG abnormal. CS for very small, very early fetus
4. After 36 weeks, babies at high risk should be delivered. Require CTG in labour (bc contractions of uterus can cause fetal hypoxia and acidaemia)
5. Transfer to special care nursery