Foetal growth

Question 1

how is fetal growth measured?

Answer 1

abdominal palpation of fundal height
symphysio-fundal height
USS: head circumference, abdominal circumference, femur length

Question 2

What is low birth weight

Answer 2

<2500g

Question 3

causes of small for gestational age

Answer 3

constitutionally small

fetal growth restriction (IUGR)

Question 4

fetal growth restriction

Answer 4

placenta-mediated growth restriction

non-placenta mediated growth restriction

Question 5

placenta-mediated growth restriction causes

Answer 5

idiopathic
pre-eclampsia
maternal smoking
maternal alcohol
anaemia
malnutrition
infection
maternal health conditions

Question 6

non-placenta mediated growth restriction causes

Answer 6

genetic abnormalities
structural abnormalities
fetal infection
errors of metabolism

Question 7

signs of fetal growth restriction

Answer 7

reduced amniotic fluid volume
abnormal Doppler studies
reduced fetal movements
abnormal CTGs

Question 8

short-term complications of FGR

Answer 8

fetal death or stillbirth
birth asphyxia
neonatal hypothermia
neonatal hypoglycaemia

Question 9

why does FGR cause increase morbidity and mortality?

Answer 9

Intrauterine hypoxia

Acidaemia

Prematurity, iatrogenic

Neonatal complications

Question 10

increased risk of which conditions in growth restricted babies?

Answer 10

Cardiovascular disease, particularly hypertension

Type 2 diabetes

Obesity

Mood and behavioural problems

Question 11

risk factors for small gestational age

Answer 11

Previous SGA baby

Recurrent fetal loss

Previous unexplained small baby

Raised AFP

Infection

Placental pathology (praevia, cirumvallata)

Obesity

Smoking, alcohol, substance abuse

Domestic violence

Prescription and OTC drugs

High altitude

Diabetes

Existing hypertension

Pre-eclampsia

Older mother (over 35 years)

Multiple pregnancy 
Low pregnancy‑associated plasma protein‑A (PAPPA) 
Haemoglobinopathies 
Collagen vascular disease 
Renal disease  
Antepartum haemorrhage 
Antiphospholipid syndrome

Question 12

high risk factors for small gestational age

Answer 12

Previous FGR is biggest risk factor

Recurrent fetal loss

Previous unexplained stillbirth

1st trimester bleeding

Smoking

Unexplained raised AFP

Question 13

reasons for small fetus

Answer 13

Normal small:
Constitutionally small, healthy baby

Abnormal small:
Chromosomal abnormalities
Syndromes
Congenital malformations

Infected small:
Infection during pregnancy
Commonly CMV

Starved small: 
Placental FGR most common cause 
Poor placentation 
Smoking 
Maternal disease affecting placenta 
Multiple pregnancy  

Wrong small:
Incorrect dates or measurements

Question 14

How to differentiate small for dates from fetal growth restriction

Answer 14

centile position
symmetry
liquor volume
UMA doppler
growth velocity

Question 15

Symphysio-fundal height <10th centile:

next step

Answer 15

serial growth scans with umbilical artery doppler

Question 16

when are women booked for serial growth scans with umbilical arteyr doppler?

Answer 16

SFH <10th centile
three or more minor risk factors
one or more major risk factos
issues with measuring SFH (large fibroids, BMI>35)

Question 17

What is measured on serial USS in women at risk or with SGA

Answer 17

Estimated fetal weight (EFW) and abdominal circumference (AC) to determine the growth velocity

Umbilical arterial pulsatility index (UA-PI) to measure flow through the umbilical artery:
End-diastolic flow velocity (continuous, absent, reversed) reflects increases in placental resistance
Essential in surveillance of the growth restricted fetus

Amniotic fluid volume

Question 18

management of small baby

Answer 18

Identifying those at risk of SGA

Confirm dates

Assess growth by ultrasound

Review measurements

Aspirin is given to those at risk of pre-eclampsia

Treating modifiable risk factors (e.g. stop smoking)

Serial growth scans to monitor growth

Early delivery where growth is static, or there are other concerns

Question 19

investigations for SGA

Answer 19

blood pressure
urine dipstick 
uterine artery doppler scanning
detailed fetal anatomy by fetal medicine
karyotyping for chromosomal abnormalities
testing for infections

Question 20

macrosomia weight at birth

Answer 20

> 4.5kg

Question 21

causes of increased symphysio-fundal height in singleton pregnancy

Answer 21

uterine fibroids
pelvic mass pushing up the uterus
polyhydramnios
obesity

Question 22

causes of macrosomia

Answer 22

Constitutional

Maternal diabetes

Previous macrosomia

Maternal obesity or rapid weight gain

Overdue

Male baby

Question 23

maternal factors causing macrosomia

Answer 23

Diabetes

Obesity

Increased maternal age

Multiparity

Large stature

Question 24

fetal factors causing macrosomia

Answer 24

constitutional
male gender
post-maturity
genetic disorder

Question 25

macrosomia risks to mother

Answer 25

Shoulder dystocia 
Failure to progress 
Perineal tears 
Operative delivery: Instrumental delivery or caesarean 
Postpartum haemorrhage 
Uterine rupture (rare) 
Prolonged labour  
Genital tract trauma

Question 26

macrosomia risks to fetus

Answer 26

Birth injury (Erbs palsy, clavicular fracture, fetal distress and hypoxia)

Perinatal asphyxia from difficult delivery

Shoulder dystocia/ Erb’s palsy

Metabolic syndrome

Neonatal hypoglycaemia

Obesity in childhood and later life

Type 2 diabetes in adulthood

Question 27

investigations for large baby

Answer 27

USS: polyhydramnios
OGTT: gestational diabetes

Question 28

prematurity weeks

Answer 28

Under 28 weeks: extreme preterm

28 – 32 weeks: very preterm

32 – 37 weeks: moderate to late preterm

Question 29

prematurity associations

Answer 29

Social deprivation 
Smoking 
Alcohol 
Drugs 
Overweight or underweight mother 
Maternal co-morbidities 
Twins 
Personal or family history of prematurity

Question 30

risk factors for prematurity

Answer 30

Spontaneous pre-term birth

Mid-trimester loss (16+)

PPROM

Cervical trauma