Fetal growth

Question 1

What is the definitions for Small for date (SGA) and Large for date (LGA)?

Answer 1

Small For Dates / SGA – describes anthropometric variables below the 10th population centile for gestational age

Large For Dates / LGA – describes anthropometric variables above the 95th population centile for gestational age

Question 2

What is the name of the growth chart using mothers details to assess for SGA/LGA?

Answer 2

Customised Antenatal Growth Chart

Question 3

What are the 3 anthropometric measurements used in ultrasound assessment of fetal size?

Answer 3

Head circumference (Biparietal diameter)

Abdominal circumference

Femur length

Question 4

What are the causes of increased morbidity and mortality in Small for date fetuses?

Answer 4

Intrauterine hypoxia
Acidaemia
Prematurity (often iatrogenic)
Neonatal complications

Question 5

What are the risk factors for Fetal Growth Restriction? (Give 5)

Answer 5

Age
BMI
Smoking
Alcohol
Substance misuse
Previous FGR
Infections (eg CMV)
Placental pathology (praevia, cirumvallata)
Hypertension

Question 6

What is Circumvallate placenta?

Answer 6

Circumvallate placenta is an abnormality of the placenta. It causes the membranes of the placenta to fold back around its edges.

It can increase the chance of complications such as preterm delivery and placental abruption, as well as increasing the risk of neonatal death and an emergency caesarean.

Question 7

Give 2 causes of Asymmetric growth (HC > AC) in SGA?
(and when does this usually present)

Answer 7

Usually presents AFTER 32 weeks

IUGR
Chronic hypoxia

Question 8

Give 2 causes of Symmetrical growth disturbances (HC=AC) in SGA?
(and when does this usually present)

Answer 8

Usually presents BEFORE 32 weeks

TORCH infections (Toxoplasmosis, Rubella, CMV, HSV)
Chronic hypoxia
Genetic conditions

Question 9

List causes fo Normal small / Abnormal small / Infected small / Starved small / Wrong small

Answer 9

Normal small&raquo_space; constitutionally small, healthy baby

Abnormal small&raquo_space; chromosomal abnormalities, syndromes, congenital malformations

Infected small&raquo_space; Infection during pregnancy (commonly CMV)

Starved small&raquo_space; “Placental FGR”, poor placentation, smoking, maternal disease affecting placenta, multiple pregnancy etc

Wrong small » Incorrect Dates or measurements

Question 10

What are the components which adequate trans-placental transfer depends on?

Answer 10

Adequate trans-placental transfer depends on:
- Uteroplacental blood flow (from the uterine artery to the placenta)
- Villous structure at the interface of maternal and fetal blood
- Fetoplacental blood flow (from umbilical arteries to the placenta)

Question 11

How can successful trophoblast invasion be assessed?

Answer 11

Successful trophoblast invasion can be assessed with a Uterine artery doppler

Question 12

What is the use of Umbilical artery doppler?

Answer 12

Umbilical artery Doppler used as a SURVEILLANCE tool of growth-restricted fetuses
- End-diastolic flow velocity (continuous, absent, reversed) reflects increases in placental resistance

Question 13

Give 3 abnormal umbilical artery waveforms

Answer 13

Abnormal umbilical artery waveforms:
a. Decreased end-diastolic velocity
b. Absent end-diastolic velocity
c. Reversed end-diastolic velocity

Question 14

What is the use of Uterine artery doppler?

Answer 14

Useful for SCREENING (NOT SURVEILLANCE), where notching identifies high risk patients

Question 15

What is the management for Absent or Reversed end-diastolic flow on Umbilical doppler?

Answer 15

With Absent or Reversed End-Diastolic Flow (AREDF) consider delivery if gestation >34/40 even in the presence of normal additional assessment

With AREDF, DELIVER BEFORE 34/40 if CTG abnormal, BPP abnormal, or other Doppler parameters are abnormal (MCA, umbilical vein)

Question 16

Give 5 causes for Large for Date presentation

Answer 16

1. Is it really large?&raquo_space; Uterine fibroids. Pelvic masses. Polyhydramnios. Maternal obesity.
2. Consider why it is large.
   - Maternal factors&raquo_space; Diabetes. Obesity. Large stature. Multiparity.
   - Fetal factors&raquo_space; Constitutional. Male gender. Postmaturity. Genetic disorders (Beckwith Wiedeman)

Question 17

What are the risks associated with a Large Fetus?

Answer 17

Maternal risks&raquo_space; Prolonged labour. Operative delivery. Postpartum haemorrhage. Genital tract trauma.

Fetal / Neonatal / Childhood risk&raquo_space; Birth trauma. Perinatal asphyxia. Shoulder dystocia. Hypoglycaemia. Childhood obesity. Metabolic syndrome.