Can Cervical Stiffness in the Second Trimester Predict Preterm Birth in High-Risk Singleton Pregnancies?

Preterm birth (PTB), defined as delivery before 37 weeks gestation, is a common complication of pregnancy and affects up to 1 in 10 women in the UK. PTB is the leading cause of neonatal mortality and morbidity with babies born earliest being at the greatest risk. Identifying women at high risk of having a PTB and offering treatments and intervention to try and prevent this outcome is a huge priority in clinical practice and in government policy.

The PRECISION study will explore the use of a new antenatal test of cervical stiffness to try and improve the recognition of women who may deliver early. Current clinical practice involves measurement of cervical length (CL) and fetal fibronectin in women known to be high risk for PTB. However recent research suggests these methods could be improved upon and we may be able to recognise women at risk more reliably and at an earlier stage in the pregnancy if we use cervical stiffness assessments.

A licensed, CE-marked, vacuum-aspiration device called the Pregnolia system has been developed to give quantitative cervical stiffness index scores during pregnancy. This study will directly compare cervical length measurements and fetal fibronectin results with cervical stiffness, using the Pregnolia system, during the second trimester in women known to be high risk for preterm birth. The investigators will aim to explore the best possible predictive tool kit bundle for PTB using any combination of these assessments.

PRECISION is a single site prospective, exploratory, cohort study of 60 women with a singleton pregnancy who are high risk for preterm birth.

Participants will have study assessments at 3 time points in second trimester as part of their routine care in high risk pre-term birth clinic. The study assessments will include transvaginal cervical length scanning, fetal fibronectin swabs and cervical stiffness assessment using the Pregnolia device.

Once recruited, participants will remain in the study until delivery and discharge from hospital. The investigators will collect routine clinical data from all participants' notes and electronic hospital records for maternal and neonatal outcomes. All study visits will coincide with routine care and all participating women will receive routine antenatal care throughout their pregnancy as per Saving Babies Lives Care Bundle V2, NICE Preterm Labour and Birth guideline and the North West Regional network preterm birth guideline.

Eligibility Criteria:
Inclusion Criteria:

* Age ≥ 18 years
* Singleton pregnancy
* Able to provide informed consent
* Meets criteria for high-risk pre-term birth clinic;

  * Previous PPROM \<34+0 weeks
  * Previous sPTB \<34+0 weeks
  * Previous spontaneous mid trimester miscarriage \>16 weeks

Exclusion Criteria:

* Previous cervical surgery including previous trachelectomy, cone biopsy, loop excision or previous cerclage
* Existing cervical cerclage (vaginal or abdominal)
* Any cervical pathology at 12 o'clock position on cervix
* Vaginal bleeding evident on examination
* Visible, symptomatic cervical or vaginal infections
* Symptomatic of preterm birth (SROM, cervical dilatation)
* Known congenital uterine anomalies
* Known or suspected structural/chromosomal fetal abnormality
* Known HIV
* Cervical carcinoma
* Previous fully dilated emergency caesarean section
* Non-English speaking if unable to provide suitable verbal translation services (language line) at the time of recruitment or subsequent study visits.