Cervical Softening and the Prediction of Preterm Birth

Currently, transvaginal cervical length measurement is used to screen in asymptomatic pregnant women with a history of PTB. In symptomatic women, presenting with threatened PTB cervical length in combination with the fibronectin test is used to identify women at high risk to deliver preterm. However, the predictive capacity of transvaginal cervical length measurement is limited. In pregnant women with a history of PTB, it only identifies a proportion of women who will have recurrent PTB. For symptomatic women, 30-60% of these women admitted to the hospital, do not deliver within seven days, leading to overtreatment of these women.

Cervical softening is precursor of cervical shortening, effacement and dilatation and therefore cervical softening is a promising new marker that is based on tissue elasticity. However, the predictive value of cervical softening and the relation with spontaneous PTB still has to be determined. With the newly developed Pregnolia® System cervical softness could be measured on a standardized and safe manner. This study could help to improve care for women with a history of spontaneous PTB.

Preterm birth (PTB) is amongst the leading causes of perinatal and childhood morbidity and mortality. Therefore, accurate identification of pregnant women at high risk of PTB is important. Identifying these women, enables obstetric healthcare professionals to apply interventions to postpone delivery and/or to prevent PTB to improve perinatal and childhood outcomes.

Currently, transvaginal cervical length measurement is used to screen asymptomatic pregnant women with a history of PTB to identify women requiring a cerclage. In symptomatic women, presenting with threatened (PTB), cervical length in combination with the fetal fibronectin(fFN) test is used to identify women at high risk to deliver within 7 days of presentation. However, the predictive capacity of transvaginal cervical length measurement is limited. In pregnant women with a history of PTB, it only identifies a proportion of women who will have recurrent PTB. For symptomatic women, 30-60% of these women admitted to the hospital, do not deliver within seven days, leading to overtreatment of these women.

Since cervical softening is a precursor of cervical shortening, effacement and dilatation, cervical softening is a promising new marker that is based on tissue elasticity. It can be measured with the CE-marked Pregnolia® System for accurate characterization of cervical softening status. It provides a value for tissue elasticity on a continuous scale.

A previous study has shown that softening of the cervix can be detected before shortening of the cervix. The Pregnolia® System may allow to detect women at risk for PTB earlier compared to traditional transvaginal ultrasound that measures shortening of the cervix, and therefore may prove useful for a more accurate risk assessment of PTB.

This current study is a single centre cohort study, where Two cohorts of women will be investigated. 1) Asymptomatic pregnant women with a history of spontaneous PTB before 34 weeks of gestation (Cohort A-STIPP). 2) Symptomatic women presenting with threatened PTB between 24 and 34 weeks (Cohort S-STIPP).

Objective: The aim of this study is to evaluate the predictive capacity of cervical softening and risk of PTB.

Eligibility Criteria:
Inclusion Criteria:

* Age 18 years or above.
* Ability to understand Dutch or English (both spoken and written).
* Ultrasound-based gestational age determined by measurement of crown rump length (CRL) determined between 9 and 11 weeks of gestation.
* Singleton and twin pregnancies.

Cohort A-STIPP specific:

- Medical history of spontaneous preterm birth before 34 weeks of gestation

Cohort S-STIPP specific:

* Threatened Preterm birth between 24 and 34 weeks of gestation.
* Threatened preterm birth is defined as:

  * abdominal pain
  * (Braxton Hicks) contractions
  * vaginal blood loss.

Exclusion Criteria:

* Under 18 years of age.
* Signs of intrauterine infection.
* Obstetric indication for immediate delivery (advanced labor, cord prolapse, abruption, signs of fetal distress).
* Confirmed fetal abnormality.
* Confirmed preterm rupture of membranes.
* Confirmed vasa / placenta praevia.
* Severe vaginal bleeding and light bleeding that cannot be stopped.
* Signs of imminent labor such as blood loss, regular contractions.