Premature Labour

Background

Defined as birth/labour occurring at < 36+6 weeks gestation and more than 22+0 weeks gestation
Around 50,000 babies are born premature every year (1.4% of births)
- Around 30% are spontaneous (idiopathic); another 30% due to multiple pregnancy
- Other risk factors include infection (main cause worldwide), preterm rupture of membranes, antepartum haemorrhage, cervical incompetence, congenital uterine abnormalities, antiphospholipid syndrome, diabetes mellitus, low maternal BMI (<19), low social class, Afro-Caribbean ethnicity, history of premature pregnancy

Diagnosis/Features

Painful uterine contractions >1:10 minutes PLUS one or more of
- Objective evidence of cervical change
- Rupture of membranes
- A ‘show’
- Cervix <1cm long and/or 2cm dilated

Investigations/Assessment

Assess foetal heart rate (NB CTG may only be used >26+0 weeks)
Speculum examination (cervical assessment; microbiology (HVS); possibility of ROM)
- Do NOT perform digital examination if SROM is suspected (safe to do so otherwise)
Also take urine sample for urinalysis and culture (infection can trigger labour)
Other investigations may include USS to check for foetal abnormality and lie/presentation if this has not already been identified

Management

Steroids should be given to all women if gestation is >24+0 and < 34+6 weeks and delivery is not imminent
- If caesarean section is being planned, consider steroid use in patients up to 38+6 weeks gestation
- In patients <24+0 weeks, consult with a specialist
- A complete course is 2 doses of dexamethasone or betamethasone 12mg IM 24 hours apart
If membranes have ruptured, consider antibiotic treatment (e.g. erythromycin 250mg QDS for 10 days or cefuroxime 1.5g TDS + metronidazole 500mg TDS +/- gentamicin if signs of sepsis)
- AVOID co-amoxiclav
Tocolysis (e.g. nifedipine)
- Only really advised in patients requiring urgent transfer to a specialist unit, those in very preterm labour or those who have not completed full dose of steroids
- Other indications include:
  - In suspected or proven pre-term labour between 24+0 and 34+0 weeks
  - If cervix is <4cm dilated
  - with intact membranes
- Relative contraindications include
  - ruptured membranes; foetal distress (delivery is more important); signs of intrauterine infection (delivery); antepartum haemorrhage; condition warranting delivery e.g. eclampsia
Magnesium sulphate may also be considered, particularly where there is ROM