Table 1 Study outcomes

At the time of device application

• Time from application of device to delivery of the cephalic pole

• Failure rate of device application (only one attempt will be made)

• Incidence of:

    ○ Operative delivery with forceps or vacuum

    ○ Caesarean section

We anticipate that there may be some cases in which the device will present the following: it cannot be applied, it is difficult to apply, it slips off, or it is ineffective. To determine the clinical circumstances under which such problems occur, the following clinical data will be collected:

• Position of head

• Station of head

• Degree of caput succedaneum and moulding

During and after delivery

• Time taken to apply the device (in seconds; from the start to the removal of the inserter)

• Successful application and inflation

• Any slipping of the device

• Number of contractions after application

• Integrity of the air chamber after expulsion

• Any other failure of the mechanical failure of the device

Immediate postpartum period until discharge (24–48 hours)

Maternal

Incidence of:

• Episiotomy

• Lacerations of the low genital tract (vulvar, vaginal or cervical trauma)

• Perineal lacerations including cervical laceration

• Third or fourth degree perineal tear

• Uterine rupture

• Pelvic hematoma

• Perineal or vaginal hematoma

• Postpartum haemorrhage as routinely monitored at the centers

• Postpartum endometritis or infection

• Maternal blood transfusion

• Maternal pain during insertion of the device

• Maternal satisfaction

Newborn

Incidence of:

• Respiratory rate at 2 hours

• Birth trauma or injuries (skull fracture, caput succedaneum, cephalohematoma, cutaneous facial lesions and facial palsy, scalp, extracranial haemorrhages, subgaleal haemorrhage, subaponeurotic haemorrhage, intracranial injuries)

• Low Apgar Scores (less than 7 at 1st minute and less than 7 at 5th minute)

• Admission to Neonatal Intensive Care Unit

• Length of stay (> 7 days) in Neonatal Intensive Care Unit

• Retinal haemorrhage

• Anaemia

• Jaundice

• Evidence of infection by local standards

• Phototherapy

• Fetal or neonatal death