Transperineal Ultrasound to Assess the Progress of Labour

Inclusion Criteria: * Gestation 24-42 completed weeks at study entry * Aged 18-44 * Cephalic * Singleton pregnancies * Nulliparous * Multiparous (excluded for the term predictive model group) * Multiple pregnancies (excluded for the term predictive model group) * Established (Active) phase of labour (included for the term predictive model group) o Clinician opinion that patient is in the established phase of labour according to the current NICE guidelines Exclusion Criteria: * Younger than 18 years. * Imminent iatrogenic intention to deliver * Life threatening maternal or fetal compromise needing immediate medical attention and/or delivery * Women who in the opinion of the researcher by virtue of language or learning impairment would be unable to give fully informed consent to the study. * Miscarriage * Intra-uterine death * Previous cervical surgery eg. cone biopsy, cervical cerclage. Note- Single LLETZ is not excluded. * Non-cephalic presentations * Multiple pregnancies (for the term predictive model group) * Multiparous patients (for the term predictive model group) * Not in established labour (for the term predictive model group)