Small for dates pregnancy

Question 1

What is a small baby defined as in centiles?

-what are the causes?

Answer 1

<10th centile

Pre-term delivery (36+6 – before 37 weeks)
o If they are born preterm they are smaller

Small for gestational age
o Intra-uterine growth restriction (IUGR)
o Consititutionally small

Question 2

What is the definition of a pre-term birth?

Answer 2

Ð Delivery between 24 and 36+6 weeks

Question 3

what are the 6 causes for pre-term birth?

Answer 3

¥ Infection

¥ ‘Over distension’ – this can stimulate the uterus to go into labour

• Multiple
• Polyhydramnios

¥ Vascular:
-Placental abruption

¥ Intercurrent illness:

• Pyelonephritis / UTI
• Appendicitis
• Pneumonia

¥ Cervical incompetence

¥ Idiopathic

Of all preterm births:
♣ 25% planned caesarean section: Severe pre-eclampsia, kidney disease or poor fetal development.
♣ 20% premature rupture of membranes
♣ 25% emergency event: Placental abruption, infection, eclampsia
♣ 40% cause unknown

Question 4

what are the 14 risk factors and assoc. for pre-term birth

Answer 4

♣ Previous PTL (20% risk X1; 40% X2))

♣ Multiple (50% risk)

♣ Uterine anomalies – bicorneate uterus

♣ Age (teenagers) - <18years old or the older mums

♣ Parity (=0 or >5)

♣ Ethnicity

♣ Poor socio-economic status

♣ Smoking

♣ Drugs (especially cocaine)

♣ Low BMI (<20)

♣ IVF

♣ <6mths between babies

♣ multiple miscarriages or abortions

♣ maternal health: poor nutrition/chronic conditions e.g. HTN/D.M

Question 5

What does small for gestational age mean?

Answer 5

Infant with a birthweight that is less than 10th centile for gestation corrected for maternal height, weight, fetal sex and birth order

Question 6

What are the three different factors that can cause poor growth of baby?

Answer 6

¥ Maternal – e.g. smoking/age of mother
¥ Fetal – e.g. chromosomal abnormality
¥ Placental – e.g. poor implantation

Question 7

What maternal factors can causes poor growth? 4

Answer 7

¥ Lifestyle:
Ð Smoking
Ð Alcohol
Ð Drugs

¥ Height and weight

¥ Age

¥ Maternal disease e.g. hypertension

Question 8

What fetal factors can cause poor growth? 3

Answer 8

¥ Infection e.g. rubella, CMV, toxoplasma
¥ Congenital anomalies e.g. absent kidneys
¥ Chromosomal abnormalities e.g. Down’s syndrome

Question 9

What placental factors can cause poor growth? 2

Answer 9

¥ Infarcts

• Small infarcts are considered to be normal and are usually at edge of placental disc
• Larger infarcts are assoc. with vascular abnormalities and can lead to placental insufficiency and death

¥ Abruption
-This is when the placenta separates fom the uterine wall and subsequent haemorrhage

Question 10

What is assymetrical vs symmetrical IUGR?

Answer 10

Symmetrical - small head and small abdo

Assymetrical - normal head and small abdo

Question 11

What are the consquences of being growth restricted antenatally or in labour? 2

Answer 11

• hypoxia

- death

Question 12

What are the consquence of being growth restricted post-natal? 6

Answer 12

Ð	Hypoglycaemia
Ð	Effects of asphyxia
Ð	Hypothermia
Ð	Polycythaemia
Ð	Hyperbilirubinaemia
Ð	Abnormal neurodevelopment

Question 13

What can suggest IUGR clinically in the antenatal clinic? 4

Answer 13

¥ Predisposing factors
¥ Fundal height less than expected
¥ Reduced liquor – reduced fluid around baby (absent kidneys/placental abnormality)
¥ Reduced fetal movements

Question 14

How is the assessment of fetal growth carried out antenatally

Answer 14

• Measure the head circumference/abdominal circumference/femur length
o Ensure that this is taken in the correct plane
o Plot these on a centile graph to assess whether a trajectory is being followed

Question 15

What does a CTG show?

Answer 15

• the fetal heartbeat and the uterine contraction are both recorded
• it is reliable indication of a normal condition of a fetus if the FHR and pattern are normal

Question 16

What is a biophysical profile and what does this consider? How is this information used?

Answer 16

¥ Ultrasound assessment

¥	Considers:
Ð	Movement
Ð	Tone
Ð	Fetal breathing movements
Ð	Liquor volume

¥ Score out of 10:
Ð 8-10 satisfactory; 4-6 repeat; 0-2 deliver

Question 17

What does an umbilical arterial doppler do?

Answer 17

• uses ultrasound to measure placental resistance to flow

shows a placenta with high resistance and reverse flow

Question 18

Umbilical artery doppler:

• what is reverse flow?
• what does absent end-diastolic flow indicate?
• what happens to blood supply in the baby if blood flow is reduced?

Answer 18

• reverse flow is blood flowing back to fetus from placenta – artery flow should always be going to placent
• if there is an absent end diastolic flow this indicates increased resistance at placenta (hypertension/infarction)

• if blood flow is reduced in a baby the brain is spared and the vessels in the brain dilate to allow more blood flow whereas the vessels everywhere else constrict
o if the middle cerebral artery shows abnormality this indicates a severe state
• if the ductus venosus Doppler is abnormal this indicates delivery as this is the last thing to become abnormal