Preterm Birth Screening (Cervical length scan)
When is it carried out?
- Women with risk factors which increase their chance of premature labour and birth should undergo serial monitoring of the length of their cervix between 12-30 weeks gestation. The precise frequency of scans is determined on an individualised basis but in the majority of cases, we recommend every two weeks.
- Routine screening for premature birth in women without risk factors is carried out at 19-24 weeks gestation. This is included as part of LPS routine second-trimester assessment.
What are the risk factors for preterm birth?
- Women who have experienced spontaneous miscarriage or preterm birth or premature rupture of the membranes (water around the baby) in a previous pregnancy between 16-36 weeks’ gestation.
- Women who have had surgery to remove part of the cervix (neck of the womb) for pre-cancerous or cancerous changes picked up on a smear test.
- Women with a congenital uterine anomaly . titch around the cervix) or progesterone therapy due to an increas (e.g bicrnuate ued chance of premature birth in a previous pregnancy
- Women with a cervical cerclage in-situ.
- Women born with a different shaped womb (e.g bicornuuate).
- Women who had a previous delivery by emergency Caesarean and were fully (10cm) dilated.
What is the purpose of preterm birth screening?
- Assess individual risk of spontaneous premature birth based on maternal factors, prior history and cervical length.
- Monitor the length of the mother's cervix (birth canal)and use this information to provide evidence-based counselling on potential interventions to reduce the risks of preterm birth and discuss these with you and your obstetrician.
What does it involve?
- A consultation
- An ultrasound scan (transvaginal ultrasound) to measure the cervix. This scan is not to examine the baby but we will show you the heartbeat for reassurance.
Where does it take place?
How long does it take?
- Approximately 15-30 minutes depending on whether it is a new or follow-up appointment.
When are the results available?
- The results of the scan are available immediately and will be discussed with you and, subsequently, directly with your obstetrician if any urgent intervention is required. If more detailed counselling is required, it may be necessary to schedule this at a later date or at the end of the clinic.