[22] Premature Labour Flashcards
What is premature labour?
The presence of contractions of sufficient length and frequency to effect progressive effacement of and dilation of the cervix before 37 weeks gestation
How many babies are born prematurely in the UK every year?
~60,000
What is considered a very premature birth?
Less than 32 weeks gestation
What % of UK births are very premature?
1.4%
What % of infant deaths are in very premature babies?
51%
What proportion of premature births have no known cause?
30%
What % of premature births are due to multiple pregnancy?
30%
What are some other risk factors for premature labour?
- Genital tract infection
- Bacterial vaginosis
- Antepartum haemorrhage
- Cervical incompetence
- Congenital uterine abnormalities
- Antiphospholipid syndrome
- DM
What is a common presenting symptom of premature labour?
Painful contractions before 37 weeks
What are many of the women experiencing when they have early painful contractions?
Braxton Hicks contractions
What percentage of women who present with early onset painful contractions have NOT delivered within 48 hours?
60%
What are some factors that indicate a woman has gone into true labour early?
- Cervical dilatation and effacement
- Vaginal bleeding in third trimester
- Heavy pressure in pelvis
- Abdominal or back pain
What ma indicate premature rupture of membranes?
A watery discharge from the vagina
When do women with suspected pre-term labour not require further investigations?
Under 29+6 weeks with intact membranes
When do women with intact membranes and are suspected to be in preterm labour require investigation?
When 30 weeks or greater
What investigations can be used to assess for preterm labour?
- Transvaginal USS measurement of cervical length
- Fetal fibronectin
- Vaginal swab
Why is transvaginal assessment of cervical length useful in assessing possible preterm labour
It estimates the likelihood of delivery within 48 hours
What finding on transvaginal ultrasound suggests preterm labour unlikely?
Cervix >15mm length
When should fetal fibronectin be used as an investigation for preterm labour?
As a quick and simple alternative to transvaginal ultrasound
What does fetal fibronectin require to be reliable?
Internal examination not to have been done first
What fetal fibronectin result is not indicative of preterm labour?
<50ng/ml
How is fetal fibronectin tested?
A swab is taken from near the cervix
Why should vaginal swabs be taken of all women with suspected preterm labour?
So appropriate antibiotic therapy can be given if infection develops
What is the priority once preterm labour has been established?
Ensure mother is taken safest available facility for delivery of a pre-term infant
What medications may need to be given to women in preterm labour?
- Tocolytic drugs
- Corticoteroids
- Magnesium sulphate
What are tocolytic agents?
Drugs that reduce contractions
Who is most likely to benefit from tocolysis in preterm labour?
- Very pre-term
- Thos needing transfer to hospital with neonatal unit
- Those hot yet completed corticosteroids
What is essentially the benefits of tocolysis?
It basically gives more time to prepare and ensure baby is delivered as late and with the best chance of survival possible
When should tocolytics not be used?
When there is P-PROM
What is the first line tocolytic drug?
Nifedipine
What is the second line tocolytic drug?
Oxytocin receptor antagonist e.g. atosiban
When should maternal corticosteroids be used in preterm labour?
If gestation is between 24 and 35+6 weeks
Why are antenatal steroids used in preterm labour?
They are associated with significant reduction in neonatal deaths, RDS and intraventricular haemorrhage
When are benefits of corticosteroids used for preterm labour seen?
Within 24 hours of the first dose
What should dosing regimes of antenatal corticosteroids provide?
24mg of betamethasone or dexamethasone IM over a 24 to 48 hour period
What is the relevance of magnesium sulphate in preterm labour?
It reduces the risk of cerebral palsy
Who should receive antenatal magnesium sulphate in preterm labour?
Women who are between 24 and 29+6 weeks and are expecting to deliver within 24 hours
Who can be considered for antenatal magnesium sulphate?
Women who are 30-33+6
How is antenatal magnesium sulphate given?
As a 4g IV bolus followed by an infusion 1g/hour over 24 hours or until delivery
What monitoring is required for magnesium sulphate?
Magnesium toxicity
When should emergency cervical cerclage be considered in preterm labour?
Women between 16 and 34 weeks with dilated cervix and exposed unruptured membranes
What is cervical cerclage?
The cervix sewn closed or partially closed
What are the contra-indications for cervical cerclage?
- Signs of infection
- Any bleeding
- Uterine contractions
How are most pre-term babies delivered if they are cephalic in presentation?
Vaginally
How are breech babies before 32 weeks delivered?
C-section
What monitoring is required during labour of a premature baby?
Fetal heart rate
How can fetal heart rate be monitored during delivery in a premature baby?
- External ultrasound (CTG)
- Intermittent auscultation
What is the prognosis of a baby born after 30 weeks with optimal care?
Most survive without any long lasting complications
What is prognosis of a baby born before 27 weeks linked to?
Gestational age
