Improving Ultrasound Based Prediction of Delivery Mode

Intrapartum Caesarean Delivery (ICD) in advanced labour has a greater fetal and maternal morbidity and mortality than an elective prelabour Caesarean delivery. The prediction of delivery mode may reduce the likelihood of intrapartum Caesarean delivery. There is also a parental desire to know the likelihood of vaginal delivery. Women admitted to delivery units throughout the world undergo internal digital vaginal examination (DVE) when they are thought to be in labour or where a diagnosis of labour needs to be discounted. DVE is an uncomfortable experience, multiple examinations have been linked to ascending maternal and fetal infection, and it is subjective method and not reliable technique to assess labour progress.

It has recently become possible to make assessments more objectively using ultrasound. Ultrasound in labour (intrapartum ultrasound) has come to the forefront in the last decade stemming from a persistent demand for a more reliable method of labour assessment coupled with a wider availability of ultrasound on the delivery suite.

The hypothesise in this study, that developing the previously derived proof of principle labour prediction model for nulliparous women and using an additional data could improve the prediction accuracy of intrapartum Caesarean delivery by developing a robust model.

Using the additional data gathered in term nulliparous patients, will develop the model to predict pregnancy outcomes. This may aid in delivery of care to pregnant women by providing a real-time online calculation tool for the likelihood of Caesarean delivery and length of labour based on repeat ultrasound measurements.

All participants will be identified by the researcher and an emphasis will be placed on recruiting patients antenatally as much as possible. All participating patients will be consented prior to enrolment and will receive a full explanatory information leaflet. If recruited antenatally, there is no time limit until the woman enters the delivery unit. If recruited in labour, then 2 hours will be considered appropriate to make a decision on whether they wish to take part and patient will only be approached when relatively pain-free (in between contractions).

The admission ultrasound scan will include if feasible fetal Doppler assessment of the Umbilical Artery (Umb A) and Middle Cerebral Artery (MCA). Amniotic Fluid Index (AFI) will also be measured. The fetal position will be assessed with a transabdominal scan and recorded.

Firstly, Umb A and MCA Doppler in addition to the fetal position and AFI, will be assessed with a transabdominal scan. After that, the transducer will be placed transperineally at the level of the posterior fourchette in a transverse position to measure HPD while caput succedaneum will be measured in a sagittal transperineal scan. The moulding will be assessed as either present or not.

During the ultrasound examination, women will be in the supine position with flexed hips and knees and the bladder empty as previously described. Healthcare professionals will be blinded to the ultrasound findings, and these findings will also not be disclosed to the parents. Another doctor or midwife will perform all the ultrasound examinations. Subsequent scans will be performed as required at the time of routine clinical examinations typically between 2-4 hours apart but it may be longer.

The healthcare professional will perform DVE for assessment of cervical dilatation in line with the National Institute of Health and Clinical Excellence (NICE) guidelines.