Pre term labour

Question 1

Define pre term labour

Answer 1

• regular painful uterine contractions associated with cervical dilation/effacement
• <37 weeks (after 24)

Question 2

Risk factors for PTL

Answer 2

• current pregnancy:
  
  • multiple
  • APH
  • infection
• previous PTL
• low BMI
• smoker
• lower socioeconomic
• race
• stress
• uterine anomalies - fibroid, bicornate

Question 3

How to predict PTL?

Answer 3

• fetal fibronectin - a glycoprotein in amniotic fluid and placental tissue
• only do it in women with symptoms of PTL
  
  • contractions
  • back pain
  • tightening
• only do it in women who are:
  
  • between 24-34 weeks GA
  • <3cm dilated on spec
  • intact membranes
• positive if >50ng/mL
  
  • negative = very unlikely she will deliver
  • less than 2% chance of delivering in 7 days
• USS detecting cervical length - transvaginal
  
  • long cervix + negative fetal fibronectin = preterm labour is highly unlikely
  • the longer the cervix the less likely she is in labour
• high vaginal swab to check for bacterial vaginosis - give dose of flagil

Question 4

Woman has positive fetal fibronectin, regular contractions at 30 wks - what is the management?

Answer 4

A) Initial management

• transfer to appropriate facility
• hydration
• bed rest
• avoid repeated pelvic exam - increased infection risk
• USS fetus (GA, position, placenta location, estimated fetal weight, BPP)
• prophylactic abx for GBS

B) Suppression of labour - tocolysis

• give tocolytics to suppress labour for 48hrs so that you can get steroids on board
• Ca channel blockers - nifedipine
• prostaglandin synthesis inhibitors - indomethacin
• magnesium sulphate
• IV salbutamol (not really used)

C) Enhancement of fetal pulmonary maturity

• betamethasone valerate
  
  • 24 - 36+6 wk

D) Cervical cerclage

• placement of cervical sutures at the level of the internal os

Question 5

What are Braxton-Hicks contractions?

Answer 5

• irregular contractions
• unchanged intensity and long intervals
• occur throughout pregnancy
• not associated with any cervical dilatation, effacement, or descent
• often relieved by rest or sedation

Question 6

Contraindications for tocolytics?

Answer 6

• any fetal or maternal reasons not to prolong pregnancy
  
  • pre eclampsia
  • eclampsia
  • chorioamnionitis
  • advanced labour
  • abruption
  • severe IUGR
  • fetal distress
  • lethal congenital abnormality

Question 7

When to give tocolysis?

Answer 7

• signs of PTL
• 24-34 weeks

Question 8

How long to give tocolytics?

Answer 8

• 48 hours until steroid loaded

Question 9

When to give steroids?

Answer 9

• 24 - 34 + 6 wks
• >35 baby will be fine
• spontaneous PTL, PPROM, elective early delivery

Question 10

Side effects of nifedipine?

Answer 10

• hypotension

Question 11

Benefits of giving steroids in pre term labour?

Answer 11

1. accelerates fetal lung maturation
2. reduces risk of neonatal death
3. reduces risk of respiratory distress syndrome
4. reduced risk of necrotising enterocolitis
5. reduced risk intraventricular haemorrhage

Question 12

When to give magnesium sulphate and why?

Answer 12

• stabilises cell membranes
• neuroprotective - reduce risk of cerebral palsy
• given to women < 30wks in PTL or needing early delivery