Preterm labour

Question 1

Define preterm labour

Answer 1

Labour <37wks

Question 2

What are the ways of preventing preterm labour?

Answer 2

3 ways of preventing:

1. Vaginal progesterone - start between 16-24wks, continue until at least 34wks.
   Indicated when any of:
   Hx of spontaneous preterm birth (<34wks) OR mid-trimester loss (>16wks) OR cervical length <2.5cm on TVUSS
2. ‘Prophylactic’ cervical cerclage
   2 Indications:
   - Hx spontaneous preterm birth (<34wks) OR mid-trimester loss, AND cervical length <2.5cm TVUSS

• Cervical length <2.5cm AND Hx of cervical trauma

3. ‘Rescue’ cervical cerclage
   Indication:
   Cervical dilatation in ABSENCE of uterine contractions (or other signs of labour) between 16-27+6 wks

Question 3

How do you manage someone who has presented with preterm labour?

Answer 3

Admit to antenatal ward

Offer IM betamethasone 24mg divided into 2 doses 12hrs apart

Offer Tocolytics (to delay delivery long enough for steroids/transfer to unit with neonatal facilities)
Contraindicated in bleeding + infection
1st line = nifedipine (CCB)
2nd line = atosiban (oxytocin receptor antagonist)

Offer IV Magnesium sulphate if birth expected in next 24hrs (neuroprotection of neonate)

• IV loading dose 4g over 5-15mins followed by IV infusion 1g/hr
• Continue infusion until birth or 24hrs (whichever is sooner)
• MUST monitor for toxicity every 4hrs as it can cause resp. depression/arrhythmias (HR, BP, RR, deep tendon reflexes)
• Antidote for toxicity = 10ml 10% Calcium gluconate over 10mins (+ STOP magnesium infusion)

Aim to deliver at 37wks

Question 4

Epidemiology?

Answer 4

About 8 in 100 babies are born preterm in the UK

Question 5

A woman who is 34wks gestation presents to triage and says she is feeling contractions. What important questions do you need to ask and what investigations/examinations will you need to do?

Answer 5

Have you felt a gush or trickle of fluid from the vagina?
Any period-type pains or backache?
Are they contractions or just foetal movements?
Are they regular contractions?

Speculum exam - check for pooling of amniotic fluid
Bloods (FBC, WCC, CRP, U&Es) for infection
Urine dipstick

CTG - record contractions and monitor foetal status

Fetal Fibronectin Test -> Tells you whether you will have preterm labour in the next 48hrs

If there is pooling of amniotic fluid, TREAT AS P-PROM

If there is NO pooling of amniotic fluid and you want to determine whether pt has already ruptured their membrane or not =
- Insulin-like growth factor binding protein‑1 test (IGF-BP1) OR
- Placental alpha-microglobulin‑1 test
(Both are swabs of vaginal fluid)