diagnosing preterm labour for women with intact membranes

Last edited 08/2019

Diagnosing preterm labour for women with intact membranes

Seek expert advice.

• offer a clinical assessment to women reporting symptoms of preterm labour who have intact membranes. This should include:
  • clinical history taking
  • the observations described for the initial assessment of a woman in labour
  • a speculum examination (followed by a digital vaginal examination (note that if a swab for fetal fibronectin testing is anticipated, the swab should be taken before any digital vaginal examination) if the extent of cervical dilatation cannot be assessed)
    
    
• if the clinical assessment suggests that the woman is in suspected preterm labour and she is 29+6 weeks pregnant or less, advise treatments as outlined for preterm labour
  
  
  
• if the clinical assessment suggests that the woman is in suspected preterm labour and she is 30+0 weeks pregnant or more, consider transvaginal ultrasound measurement of cervical length as a diagnostic test to determine likelihood of birth within 48 hours. Act on the results as follows:
  • if cervical length is more than 15 mm, explain to the woman that it is unlikely that she is in preterm labour and:
    • think about alternative diagnoses
    • discuss with her the benefits and risks of going home compared with continued monitoring and treatment in hospital
    • advise her that if she does decide to go home, she should return if symptoms suggestive of preterm labour persist or recur
  • if cervical length is 15 mm or less, view the woman as being in diagnosed preterm labour and offer treatment measures for preterm labour (tocolysis, maternal corticosteroids)
    
    
• fetal fibronectin testing should be considered as a diagnostic test to determine likelihood of birth within 48 hours for women who are 30+0 weeks pregnant or more if transvaginal ultrasound measurement of cervical length is indicated but is not available or not acceptable. Act on the results as follows:
  • if fetal fibronectin testing is negative (concentration 50 ng/ml or less), explain to the woman that it is unlikely that she is in preterm labour and:
    • think about alternative diagnoses
    • discuss with her the benefits and risks of going home compared with continued monitoring and treatment in hospital
    • advise her that if she does decide to go home, she should return if symptoms suggestive of preterm labour persist or recur
  • if fetal fibronectin testing is positive (concentration more than 50 ng/ml), view the woman as being in diagnosed preterm labour and offer treatment measures for preterm labour (tocolysis, maternal corticosteroids)
    
    
• if a woman in suspected preterm labour who is 30+0 weeks pregnant or more does not have transvaginal ultrasound measurement of cervical length or fetal fibronectin testing to exclude preterm labour, offer treatment consistent with her being in diagnosed preterm labour
  
  
• do not use transvaginal ultrasound measurement of cervical length and fetal fibronectin testing in combination to diagnose preterm labour

Reference:

• NICE (August 2019).Preterm labour and birth