Premature Labour Flashcards
What is meant by SROM, PROM and P-PROM?
SROM:
- spontenous rupture of the membranes
PROM:
- premature rupture of the membranes (before the onset of labour)
P-PROM:
- preterm premature rupture of the membranes
- rupture before the onset of labour and before 37 weeks gestation
rupture of the membranes refers to rupturing of the amniotic sac
What is another meaning of PROM?
prolonged rupture of the membranes
- rupture of the amniotic sac more than 18 hours before delivery
How is prematurity defined?
birth before 37 weeks gestation
the more premature = the worse the outcomes
When are babies considered non-viable?
- if they are born before 23 weeks gestation
- resuscitation is NOT considered in babies born between 23-24 weeks if they do not show signs of life
full resuscitation is offered after 24 weeks as there is an increased chance of survival
How does the WHO classify prematurity?
extreme preterm:
- under 28 weeks
very preterm:
- from 28 to 32 weeks
moderate to late preterm:
- from 32 to 37 weeks
What is the main way of preventing preterm labour?
vaginal progesterone
- a pessary / gel is inserted into the vagina
- progesterone prevents labour by decreasing the activity of the uterus and preventing the cervix from remodelling
Who is suitable for vaginal progesterone?
- women with a cervical length < 25mm on vaginal USS
- between 16 and 24 weeks gestation
What is cervical cerclage?
- a stitch is put in the cervix to add support + keep it closed
- this requires spinal or general anaesthetic
- the stitch is removed when the woman reaches term / goes into labour
Who is suitable for cervical cerclage?
- women with a cervical length < 25mm on vaginal USS
- between 16 and 24 weeks gestation
AND
- previous preterm birth or cervical trauma (e.g. colposcopy)
What is “rescue” cervical cerclage?
- cervical cerclage offered between 16 and 27 + 6 weeks
- where there is cervical dilatation WITHOUT ROM
- this prevents progression + premature delivery
What is preterm premature rupture of membranes (P-PROM)?
- the amniotic sac ruptures to release amniotic fluid
- occurring before the onset of labour
- in a preterm pregnancy (before 37 weeks gestation)
How is rupture of the membranes diagnosed?
speculum examination
- pooling of amniotic fluid in the vagina is seen
- no tests required
If there is doubt about ROM, what tests can be performed?
insulin-like growth factor-binding protein-1 (IGFBP-1):
- a protein present in high concentrations in the amniotic fluid
- tested in vaginal fluid where there is doubt about ROM
placental alpha-microglobulin-1 (PAMG-1):
- an alternative to IGFBP-1
What should NOT be attempted where ROM is suspected?
digital vaginal examination
- there is a risk of introducing infection through the vaginal canal
How might someone with P-PROM present?
What investigations are performed?
- assess maternal pulse + temperature
- there will be abdominal tenderness on palpation
other investigations include:
- FBC (for WCC)
- CRP
- HVS (high vaginal swab)
- MSU
- CTG
- USS (to check for obvious fluid leakage)
What is medication is given to the mother in P-PROM?
prophylactic antibiotics
- to prevent development of chorioamnionitis
- erythomycin 250mg 4x daily for 10 days
OR
- until labour is established
chorioamnionitis = infection of placenta + amniotic fluid
When can IOL be offered in P-PROM?
- IOL can be offered from 34 weeks
- treatment aims to keep the baby in place until this point
- mother is monitored for signs of infection / labour until this point
What other medication is given to the mother in P-PROM?
prophylactic steroids
- betamethasone 12mg IM
- given as 2 doses that are 24 hours apart
- this speeds up maturity of foetal lungs
Does someone with P-PROM need to be admitted?
- they should be admitted for 48 hours for monitoring
- IM steroids are administered
- they can then be sent home if there is no evidence of infection / onset of labour
What is involved in preterm labour with intact membranes?
- regular painful contractions and cervical dilatation
- WITHOUT rupture of the amniotic sac
How is preterm labour with intact membranes assessed?
speculum examination
- this is used to assess for cervical dilatation
How can preterm labour be diagnosed before 30 weeks gestation?
- clinical examination with a speculum is sufficient to offer management
- this looks for evidence of cervical dilatation
How is preterm labour diagnosed after 30 weeks gestation?
transvaginal USS:
- this assesses the cervical length
- if cervical length is < 15mm, management of preterm labour is offered
- if cervical length > 15mm, preterm labour is unlikely
What is an alternative test to vaginal US to assess likelihood of premature labour?
fetal fibronectin
- it is found in the vagina during labour
- a result < 50 ng/ml is negative
- this means preterm labour is unlikely
What are the 5 options for improving outcomes in preterm labour?
- maternal corticosteroids
- fetal monitoring via CTG
- IV magnesium sulphate
- tocolysis with nifedipine
- delayed cord clamping
What is tocolysis?
the use of medications to stop uterine contractions
Which medications are used for tocolysis in premature labour?
- nifedipine is the first line
- atosiban is an oxytocin receptor antagonist that can be used when nifedipine is contraindicated
nifedipine = CCB
When can tocolysis be used in preterm labour?
- it can be used between 24 and 33 + 6 weeks gestation
- it can only be used as a short term measure for < 48 hours
What is the purpose of tocolysis in preterm labour?
- it can delay delivery to buy time for:
- administration of maternal steroids
- transfer to a more specialist unit (neonatal ICU)
What is the purpose of maternal corticosteroids?
- they speed up development of the foetal lungs
- this reduces the risk of respiratory distress syndrome after birth
When are maternal corticosteroids appropriate?
women with suspected preterm labour of babies < 36 weeks gestation
Why is IV magnesium sulphate given in preterm labour?
- it protects the fetal brain during preterm delivery
- it reduces the risk / severity of cerebral palsy
When is IV magnesium sulphate given?
What is the dose?
- it is given within 24 hours of delivery of preterm babies of < 34 weeks gestation
- given as a bolus followed by infusion for up to 24 hours or until birth
Why do mothers need close monitoring when IV magnesium sulphate is given?
- they need close monitoring of observations and tendon reflexes for signs of magnesium toxicity
- signs of magnesium toxicity include:
- reduced RR
- reduced BP
- absent reflexes
