Obstetric Examination Findings

Question 1

What can cause a baby to be SGA?

Answer 1

Normal (Constitutionally) Small:
ethnicity, sex, and parental height may contribute

Placenta Mediated Growth Restriction
(conditions that affect the transfer of nutrients across the placenta):
Pre-eclampsia, maternal smoking /alcohol, anaemia, malnutrition, infection

Non-Placenta Mediated Growth Restriction:
Growth is affected by fetal factors such as a chromosomal or structural anomaly, an error in metabolism or fetal infection

Question 2

What can be used for surveillance of SGA?

Answer 2

Women are booked for serial growth scans with umbilical artery doppler if they have:

Three or more minor risk factors
One or more major risk factors
Issues with measuring the symphysis fundal height (e.g. large fibroids or BMI > 35)

If UAD is normal induction can be offered at 37 weeks

Question 3

List some complications of SGA

Answer 3

stillbirth, birth asphyxia, hypothermia, obesity and cancer

Question 4

What can cause macrosomia?

Answer 4

Constitutional, Male baby, Overdue
Previous macrosomia
Maternal diabetes
Maternal obesity or rapid weight gain

Question 5

What are the risks of macrosomia to the mother ?

Answer 5

Shoulder dystocia
Failure to progress
Perineal tears
Uterine rupture (rare)
Instrumental delivery or caesarean
Postpartum haemorrhage

Question 6

What are the risks of macrosomia to the baby ?

Answer 6

Birth injury (Erbs palsy, clavicular fracture, fetal distress and hypoxia)
Neonatal hypoglycaemia
Obesity in childhood and later life
Type 2 diabetes in adulthood

Question 7

How should an LGA baby be investigated?

Answer 7

Ultrasound to exclude polyhydramnios and estimate the fetal weight
Oral glucose tolerance test for gestational diabetes

Question 8

How can risk be reduced when delivering an LGA baby?

Answer 8

Delivery on a consultant lead unit
Delivery by an experienced midwife or obstetrician
Access to an obstetrician and theatre if required
Active management of the third stage (delivery of the placenta)
Early decision for caesarean section if required
Paediatrician attending the birth

Question 9

Define fetal lie

Answer 9

the relationship between the long axis of the fetus and the mother.
Longitudinal, transverse or oblique

Question 10

Define fetal presentation
What is the most common presentation?

Answer 10

the fetal part that first enters the maternal pelvis

Cephalic vertex presentation is the most common and is considered the safest

Other presentations include breech, shoulder, face and brow

Question 11

Define fetal position

Answer 11

the position of the fetal head as it exits the birth canal.
Usually the fetal head engages in the occipito-anterior position (the fetal occiput facing anteriorly) – this is ideal for birth

Question 12

Define polyhydramnios

Answer 12

the presence of amniotic fluid >95th centile

Question 13

What can cause polyhydramnios?

Answer 13

Usually idiopathic

Macrosomia – larger babies produce more urine

Maternal diabetes – especially if poorly controlled

Maternal ingestion of lithium – leads to fetal diabetes insipidus

Any condition that prevents the fetus from swallowing – e.g. oesophageal atresia, muscular dystrophies, congenital diaphragmatic hernia

Duodenal atresia – ‘double bubble’ sign on ultrasound scan

Anaemia

Fetal hydrops

Genetic or chromosomal abnormalities