Premature Labour

Question 1

What is meant by SROM, PROM and P-PROM?

Answer 1

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

Question 2

What is another meaning of PROM?

Answer 2

prolonged rupture of the membranes

• rupture of the amniotic sac more than 18 hours before delivery

Question 3

How is prematurity defined?

Answer 3

birth before 37 weeks gestation

the more premature = the worse the outcomes

Question 4

When are babies considered non-viable?

Answer 4

• 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

Question 5

How does the WHO classify prematurity?

Answer 5

extreme preterm:

• under 28 weeks

very preterm:

• from 28 to 32 weeks

moderate to late preterm:

• from 32 to 37 weeks

Question 6

What is the main way of preventing preterm labour?

Answer 6

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

Question 7

Who is suitable for vaginal progesterone?

Answer 7

• women with a cervical length < 25mm on vaginal USS
• between 16 and 24 weeks gestation

Question 8

What is cervical cerclage?

Answer 8

• 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

Question 9

Who is suitable for cervical cerclage?

Answer 9

• 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)

Question 10

What is “rescue” cervical cerclage?

Answer 10

• cervical cerclage offered between 16 and 27 + 6 weeks
• where there is cervical dilatation WITHOUT ROM
• this prevents progression + premature delivery

Question 11

What is preterm premature rupture of membranes (P-PROM)?

Answer 11

• the amniotic sac ruptures to release amniotic fluid
• occurring before the onset of labour
• in a preterm pregnancy (before 37 weeks gestation)

Question 12

How is rupture of the membranes diagnosed?

Answer 12

speculum examination

• pooling of amniotic fluid in the vagina is seen
• no tests required

Question 13

If there is doubt about ROM, what tests can be performed?

Answer 13

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

Question 14

What should NOT be attempted where ROM is suspected?

Answer 14

digital vaginal examination

• there is a risk of introducing infection through the vaginal canal

Question 15

How might someone with P-PROM present?

What investigations are performed?

Answer 15

• 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)

Question 16

What is medication is given to the mother in P-PROM?

Answer 16

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

Question 17

When can IOL be offered in P-PROM?

Answer 17

• 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

Question 18

What other medication is given to the mother in P-PROM?

Answer 18

prophylactic steroids

• betamethasone 12mg IM
• given as 2 doses that are 24 hours apart
• this speeds up maturity of foetal lungs

Question 19

Does someone with P-PROM need to be admitted?

Answer 19

• 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

Question 20

What is involved in preterm labour with intact membranes?

Answer 20

• regular painful contractions and cervical dilatation
• WITHOUT rupture of the amniotic sac

Question 21

How is preterm labour with intact membranes assessed?

Answer 21

speculum examination

• this is used to assess for cervical dilatation

Question 22

How can preterm labour be diagnosed before 30 weeks gestation?

Answer 22

• clinical examination with a speculum is sufficient to offer management
• this looks for evidence of cervical dilatation

Question 23

How is preterm labour diagnosed after 30 weeks gestation?

Answer 23

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

Question 24

What is an alternative test to vaginal US to assess likelihood of premature labour?

Answer 24

fetal fibronectin

• it is found in the vagina during labour
• a result < 50 ng/ml is negative
• this means preterm labour is unlikely

Question 25

What are the 5 options for improving outcomes in preterm labour?

Answer 25

• maternal corticosteroids
• fetal monitoring via CTG
• IV magnesium sulphate
• tocolysis with nifedipine
• delayed cord clamping

Question 26

What is tocolysis?

Answer 26

the use of medications to stop uterine contractions

Question 27

Which medications are used for tocolysis in premature labour?

Answer 27

• nifedipine is the first line
• atosiban is an oxytocin receptor antagonist that can be used when nifedipine is contraindicated

nifedipine = CCB

Question 28

When can tocolysis be used in preterm labour?

Answer 28

• it can be used between 24 and 33 + 6 weeks gestation
• it can only be used as a short term measure for < 48 hours

Question 29

What is the purpose of tocolysis in preterm labour?

Answer 29

• it can delay delivery to buy time for:
• administration of maternal steroids
• transfer to a more specialist unit (neonatal ICU)

Question 30

What is the purpose of maternal corticosteroids?

Answer 30

• they speed up development of the foetal lungs
• this reduces the risk of respiratory distress syndrome after birth

Question 31

When are maternal corticosteroids appropriate?

Answer 31

women with suspected preterm labour of babies < 36 weeks gestation

Question 32

Why is IV magnesium sulphate given in preterm labour?

Answer 32

• it protects the fetal brain during preterm delivery
• it reduces the risk / severity of cerebral palsy

Question 33

When is IV magnesium sulphate given?

What is the dose?

Answer 33

• 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

Question 34

Why do mothers need close monitoring when IV magnesium sulphate is given?

Answer 34

• they need close monitoring of observations and tendon reflexes for signs of magnesium toxicity
• signs of magnesium toxicity include:

1. reduced RR
2. reduced BP
3. absent reflexes