Developmental Abnormalities

Question 1

What is the genetic defect in Patau’s syndrome and Edwards’ Syndrome?

Answer 1

Patau syndrome: Trisomy 13

Edwards’ syndrome: Trisomy 18

Question 2

What is the name of the condition for Trisomy 21?

Answer 2

Down’s syndrome

Question 3

What is “Small for Gestational Age”?

Answer 3

SGA is an infant born with a birthweight less than 10th percentile.

Question 4

How is Small for Gestational Age (SGA) in a fetus diagnosed?

Answer 4

SGA is diagnosed by ultrasound. Estimated fetal weight <10th percentile, or Abdominal Circumference <10th percentile.

Question 5

Who are those at risk of delivering SGA babies?

Answer 5

Women who are underweight (BMI <18.5), malnourished, smokes >10 per day, Cocaine abuse, daily vigorous exercise, previous SGA babies, chronic hypertension.

Question 6

What is PAPP-A?

Answer 6

PAPP-A is Pregnancy-associated Plasma protein A.

It is a placental hormone used for identification of pregnancy risk in early pregnancy.

Question 7

What is the significance of PAPP-A?

Answer 7

Reduced PAPP-A in the 1st trimester may indicate chromosomal abnormalities such as Down’s syndrome.
Low levels also constitutes a high risk for IUGR, placental abruption and stillbirth.

Question 8

What tests are done to determine if there is Small for gestational age?

Answer 8

Uterine artery ultrasound and blood tests for PAPP-A levels

Question 9

What is the most common cause of SGA?

Answer 9

Utero-placental insufficiency.

Question 10

How does the uterine artery ultrasound detects?

Answer 10

The uterine artery ultrasound indirectly measures resistance to umbilical artery blood flow from the fetus to the mother via the placenta.

Question 11

What does reduced blood flow indicate in uterine artery ultrasound? What are the next steps taken?

Answer 11

Reduced blood flow or increasing resistance indicates high risk of hypoxaemia of fetus. Survey twice a week, and probably deliver within 36-37 weeks.

Question 12

What does absent blood flow or reversed blood flow indicate in the uterine artery ultrasound test? What are the next steps?

Answer 12

Absent or reversed blood flow are early signs of fetal hypoxaemia and indicates high risk of perinatal death.
Daily surveillance, Discuss delivery plan and administer steroids if needed.

Question 13

Define Macrosomia.

Answer 13

Macrosomia is birth weight >4.5kg (9 pounce 15 ounces) regardless of gestational age.

Question 14

What are the signs of macrosomia in pregnancy?

Answer 14

Increased symphyseal-fundus height, and polyhydramnios.

Question 15

What are the complications for the mother in macrosomia?

Answer 15

1. Genital tract laceration
2. Labor problems as the fetus may get wedged in the birth canal
3. Sometimes, C-section will be needed.
4. Postpartum haemorrhage - atonic uterus
5. Uterine rupture if mother has previous C-section or major uterine surgery

Question 16

What are the complications of macrosomia that can befall on the child?

Answer 16

1. Metabolic syndrome during childhood: a combination of high BP, high blood sugar levels, high cholesterol, and excess body fat around the waist, leading to increase risk of heart conditions, stroke and diabetes.
2. Shoulder dystocia
3. Childhood obesity
4. Lower than normal blood sugar level

Question 17

What is done about macrosomia?

Answer 17

4 weekly ultrasound scan between 28-36 weeks of gestation.

Question 18

Why will (gestational) diabetes lead to macrosomia?

Answer 18

This is due to increased fetal blood glucose concentrations which will induce hyperinsulinaemia, causing fetal fat deposition and excessive growth (macrosomia).