RANZCOG guideline - Fetal macrosomia

Question 1

list 8 risk factors for fetal macrosomia

Answer 1

• maternal diabetes
• maternal obesity
• ethnicity
• prior h/o LGA/macrosomic baby
• maternal age >30 y
• high parity
• post term pregnancy
• excessive maternal weight gain

Question 2

a woman presents to you asking for an IOL at 38/40 because her baby is >95th centile. How would you counsel her?

Answer 2

The benefit of induction of labour before 39+0 weeks of gestation in the presence of ultrasound confirmed fetal macrosomia of EFW >95th centile (namely, reduction of clinically significant shoulder dystocia and fractures in the neonate) must be weighed against the challenges with the ultrasound diagnosis of fetal macrosomia as well as the short-term and long-term outcomes for babies born before 39+0 weeks gestation.

Question 3

For what sized babies is Elective CS routinely offered?

Answer 3

• non diabetic mother - EFW >5kg

- diabetic mother - EFW >4.5kg

Question 4

For the prediction of brith weight ?4kg what is the sensitivity and specificity of USS?

Answer 4

• 56% sensitivity

- 92% specificity

Question 5

What percentage of USS estimated fetal weights >4.5kg are accurate?

Answer 5

33-44%

Question 6

List 4 maternal risks of fetal macrosomia?

Answer 6

• Caesarean birth (due to labour dystocia) - EFW >4.5kg risk of CS is double that of non macrosomic baby
• PPH (OR 3.1)
• chorioamnionitis (OR 2.4)
• 3rd or 4th degree tear (OR 1.7)

Question 7

List 4 maternal risks of fetal macrosomia?

Answer 7

• Caesarean birth (due to labour dystocia) - EFW >4.5kg risk of CS is double that of non macrosomic baby
• PPH (OR 3.1)
• chorioamnionitis (OR 2.4)
• 3rd or 4th degree tear (OR 1.7)

Question 8

List 6 fetal risks of fetal macrosomia

Answer 8

• shoulder dystocia (OR 7.1)
• injuries associated with shoulder dystocia e.g. clavicle fracture which is a 10 fold increased risk in the presence of macrosomia)
• low 5 minute Apgar score
• hypoglycaemia
• rates of admission to NICU
• overweight, obesity and metabolic syndrome later in life

Question 9

List 6 fetal risks of fetal macrosomia

Answer 9

• shoulder dystocia (OR 7.1)
• injuries associated with shoulder dystocia e.g. clavicle fracture which is a 10 fold increased risk in the presence of macrosomia)
• low 5 minute Apgar score
• hypoglycaemia
• rates of admission to NICU
• overweight, obesity and metabolic syndrome later in life

Question 10

Compared with expectant management, IOL for suspected macrosomia is associated with:

Answer 10

• reduction in shoulder dystocia RR 0.6
• reduction in any type of fracture RR 0.2
• no difference in CS rates

Question 11

List 3 strategies to prevent macrosomia

Answer 11

• strength conditioning exercise
• control of maternal hyperglycaemia
• bariatric prior to pregnancy for women with severe obesity

Question 11

List 3 strategies to prevent macrosomia

Answer 11

• strength conditioning exercise
• control of maternal hyperglycaemia
• bariatric prior to pregnancy for women with class III obesity