Preterm Labour

Question 1

Define pre-term labour.

Answer 1

Onset of contractions before 37 weeks gestation

Question 2

Define the categories of pre-term labour.
(Extreme, severe, premature, near term)

Answer 2

Extreme = <28 weeks
Severe = 28-32 weeks
Premature = 32-34 weeks
Near term = 34-36+6 weeks

Question 3

Give 3 risk factors for PTL for each of the following: maternal factors, obstetric history, pregnancy complications

Answer 3

Maternal: smoker, malnutrition, extremes of age

Obstetric Hx: short cervix, cervical surgery, TOP

Pregnancy Comps: infection, twins, Hx PTL

Question 4

List 8 complications of pre-term labour.

Answer 4

1. Neonatal death
2. RDS
3. Hypothermia
4. Hypoglycaemia
5. Jaundice
6. Infection
7. IVH
8. Long term developmental delay

Question 5

Give 5 causes of pre-term labour.

Answer 5

Stress (maternal or foetal)
Stretch (uterine distension)
Infection
Malnutrition
Cervical incompetence

Question 6

What two parameters are measured on TVUS in pre-term labour?

Answer 6

Cervical length
Funnelling (opening of internal os with closed cervix)

Question 7

What is a foetal fibronectin test (FFT)?

Answer 7

ECM glycoproteins from amniotic membranes - found in vaginal secretions before labour (high levels - high chance of labour)

Question 8

How is PTL diagnosed?

Answer 8

1. Exam (obstetric, speculum)
2. Regular contractions + cervical changes + ROM

Question 9

What agents are used in tocolysis?

Answer 9

1. Atosiban
2. Nifedipine
3. Corticosteroids

Question 10

What are the types and doses of corticosteroids for foetal lung maturity?

Answer 10

Dexamethasone - 2 doses, 12mg IM, 12 hours apart
Betamethasone - 2 doses, 12mg IM, 24 hours apart

Question 11

Give 5 indications for tocolysis.

Answer 11

1. Healthy foetus
2. No C/I to the drug or prolongation of pregnancy
3. Clear diagnosis of PTL
4. Cervix <4cm dilated
5. Gestational age 24-34 weeks

Question 12

Give 5 contraindications for tocolysis.

Answer 12

1. Severe haemorrhage
2. Severe pre-eclampsia
3. Intrauterine death
4. Placental abruption
5. GA >34 weeks

Question 13

When can tocolysis not be used?

Answer 13

1. ROM unless transfer
2. Active labour
3. Allergy or contraindication

Question 14

What determines the mode of delivery in PTL?

Answer 14

If the pregnancy is viable - deliver via the route that will cause the least trauma/distress

Cephalic presentation - vaginal delivery
Foetus <26 weeks - C-section is hazardous
Avoid Kiwi <34 weeks

Question 15

Which drug is licensed for tocolysis?

Answer 15

Atosiban (competitive oxytocin antagonist)

Question 16

What preventative procedure can be performed at 14 weeks if the cervix is effacing or dilating at a pre-viable gestation?

Answer 16

Cervical suture

Question 17

When is a cervical suture placed and removed?

Answer 17

Placed at 14w, removed at 36w