Clinical Guidelines

The Australian Preterm Birth Prevention Alliance aims to safely lower the rate of preterm birth by combining the latest evidence-based clinical practice with educational outreach programs for health care practitioners and the general public.

On-going discovery research and evaluation of effectiveness will ensure the Initiative remains responsive in this rapidly changing field of medicine.

The Key Practice Points include:

  • Measurement of cervix length is to be included in all mid-pregnancy morphology scans, conducted routinely at 18-20 weeks gestation as well as for any other scan between 16 and 24 weeks. In those cases in which the cervix can be imaged clearly on trans-abdominal scan, a closed length from internal to external os of 35 mm or more is adequate. In all other cases trans-vaginal scanning is required at which a closed cervix length of 25mm or less is considered shortened. The different cut-off measurements between these two techniques are due to the fact that the cervix may be stretched by the full bladder at trans-abdominal scan. Trans-vaginal scans are performed with an empty bladder and hence the true length is measured. Please note that cervix length is a powerful predictor of risk of preterm birth, but only between 16 and 24 weeks gestation – before and after these ages the test is weak and is not recommended.
  • Natural vaginal progesterone 200mg pessary to be prescribed nightly for any case in which the cervix has been found on ultrasound imaging to be shortened at any time between 16 and 24 weeks gestation. Treatment to continue until 36 weeks gestation.
  • In cases in which the cervix length is less than 10mm on transvaginal imaging, management can include cervical cerclage, vaginal progesterone, or both.
  • Natural vaginal progesterone 200mg pessaries to be prescribed for all cases in which there is a history of spontaneous preterm birth (with or without preterm pre-labour rupture of membranes) between 20 and 34 weeks gestation and to be used each night from 16 to 36 weeks gestation.
  • No pregnancy is to be ended prior to 39 weeks’ gestation unless there is a medical or obstetric justification.
  • Women who smoke should be identified and offered counselling though one of the well-established Quitline services offered through state and territory-based Departments of Health.