Small and Large for dates babies

Question 1

What is the definition of small for gestational age babies?

Answer 1

Infants born with a birth weight of <10th centile.

Question 2

What is the difference between SGA and IUGR definitions?

Answer 2

SGA definition is based on neonates’ birth weights being less than the 10th centile. It doesn’t take into consideration the in-utero growth and physical characteristics at birth.

IUGR is a clinical definition and applies to neonates with clinical features of malnutrition and IUGR, irrespective of their birth weight percentile.

Question 3

What are the major risk factors of SGA?

Answer 3

1. Maternal age >40yo.
2. Smokes >10 cigarettes per day.
3. Previous SGA babies or previous stillbirths
4. Daily vigorous exercise
5. Cocaine use.
6. Diabetes with vascular disease
7. Pregnancy-associated plasma protein-A (PAPP-A) <0.4
8. Renal impairment
9. Chronic hypertension
10. Antiphospholipid syndrome

Question 4

What are the minor risk factors of SGA?

Answer 4

1. Maternal age >/-35
2. Smokes 1-10 cigarettes per day
3. BMI <20
4. Previous pre-eclampsia
5. Pregnancy interval <6months or >60months

Question 5

What is the guidelines in place for early prediction of a SGA neonate?

Answer 5

Serial measurement of symphysis fundal height (SFH) is recommended at each antenatal appointment from 24 weeks as it improves prediction of an SGA baby.

Question 6

Which 3 conditions can result in inaccurate SFH measurements? What is the next course of action?

Answer 6

BMI >35, hydramnios and large fibroids can result in inaccurate SFH measurements.
These women are referred for serial assessment of fetal size using ultrasound.

Question 7

What interventions are there for the prevention of SGA neonates?

Answer 7

Anti-platelet agents may be effective in preventing SGA in women at high risk of pre-eclampsia. This should be commenced at, or before, 16 weeks.

Question 8

When should Aspirin be commenced in the prevention of SGA neonates for women at high risk of pre-eclampsia?

Answer 8

Should be commenced before 16 weeks.

Question 9

Which medication is associated with an increased risk of a SGA neonate?

Answer 9

Beta-blockers.

Hence, avoid atenolol.

Question 10

What is the definition of macrosomia?

Answer 10

Birth weight of >4.5kg, regardless of gestational age.

Question 11

What are the newborn and childhood complications from macrosomia?

Answer 11

1. Shoulder dystocia
2. lower than normal blood glucose level
3. Metabolic syndrome during childhood: high BP, high BMI, excess body fat around the waist, high blood sugar, increased risk of heart conditions due to abnormal cholesterol levels
4. Childhood obesity

Question 12

What are the infections that can possibly cause SGA/IUGR?

Answer 12

Toxoplasmosis, CMV, Malaria and Syphilis.

Serology screening for congenital CMV and for Toxoplasmosis, Malaria and syphilis

Question 13

What are to be considered as possible reasons of Large for Gestational Age babies?

Answer 13

• Gestational diabetes
• Polyhydramnios
• Multiple pregnancy
• Fibroids
• Ovarian cysts or tumours
• Wrong dates

Question 14

What are the complications to the mother with a macrosomic baby?

Answer 14

1. Problems in labour, such as the baby being wedged in the birth canal

Question 15

What are the maternal factors that can affect placental transfer of nutrients?

Answer 15

1. Low pre-pregnancy weight
2. Under nutrition
3. Substance abuse - Nicotine abuse for example
4. Severe anaemia

Question 16

What are the medical conditions that can interfere with placental implantation and vasculature, thereby affecting transfer of nutrients?

Answer 16

Pre-eclampsia
Autoimmune diseases
Thrombophilia
Renal disease
Diabetes
Essential hypertension