A multi-centre randomised controlled trial of ultrasound assessment of the fetal head position versus standard care as an approach to prevent morbidity at instrumental delivery
IDUS - Instrumental Delivery and UltraSound
The hypothesis is that an abdominal ultrasound scan performed in addition to routine clinical assessment reduces the incidence of incorrect diagnosis of the fetal head position which will reduce the risk of maternal and perinatal morbidity.
Granted by the Research Ethics Committee of the Coombe Women & Infants University Hospital Dublin on the 5th October 2010
Multicentre individually randomised parallel two-arm trial
Primary study design
Secondary study design
Randomised controlled trial
Patient information sheet
Not available in web format, please use the contact details below to request a patient information sheet
Fetal head position in labour
Eligible women who have consented to participate in the trial will be allocated to either the usual care arm or intervention arm. Women allocated to receive usual care will be managed according to RCOG guidelines and the local hospital protocol.
Women in the intervention group will be managed in the same way. In addition they will receive an ultrasound scan to assess the position of the fetal head and spine.
In both groups, the mother and the neonate will be followed-up until hospital discharge.
Primary outcome measure
Incorrect diagnosis of the fetal head position
Secondary outcome measures
Secondary neonatal outcomes will include trauma, low Apgar scores, low arterial blood gases and admission to the neonatal intensive care unit (NICU). Neonatal trauma will include bruising, laceration, cephalhaematoma, retinal haemorrhage, facial nerve palsy, brachial plexus injury and fractures. Paired cord blood gases will be taken routinely to measure arterial and venous pH and base excess. Arterial pH below 7.10 and base excess greater than -12.0 mmol/l will be used as the threshold to define significant fetal acidosis.
Secondary maternal outcomes will include extensive perineal tearing involving the anal sphincter (third or fourth degree tears), postpartum haemorrhage, shoulder dystocia, and length of postnatal hospital stay. Primary post partum haemorrhage is defined as an estimated blood loss at delivery and in the first 24 hours of more than 500mls. Postnatal stay will be considered prolonged if more than 3 days' duration. Maternal and neonatal complications will be defined clinically according to the attending clinicians.
Overall trial start date
Overall trial end date
Reason abandoned (if study stopped)
Participant inclusion criteria
The study will be limited to nulliparous women at term with singleton cephalic pregnancies, aiming to deliver vaginally who require an instrumental delivery in the second stage of labour.
Target number of participants
Participant exclusion criteria
Women with a contraindication to instrumental delivery, or who have a limited understanding of English or are under 18 years of age.
Recruitment start date
Recruitment end date
Countries of recruitment
Trial participating centre
The Coombe Women and Infants University Hospital
The Coombe Women and Infants University Hospital (Ireland)
Health Research Board (Ireland)
Funding Body Type
private sector organisation
Funding Body Subtype
Results and Publications
Publication and dissemination plan
Not provided at time of registration
Intention to publish date
Participant level data
Not provided at time of registration
Basic results (scientific)
1. 2012 protocol in http://www.ncbi.nlm.nih.gov/pubmed/22970933
Murphy DJ, Burke G, Montgomery AA, Ramphul M, , Study protocol. IDUS - Instrumental delivery & ultrasound: a multi-centre randomised controlled trial of ultrasound assessment of the fetal head position versus standard care as an approach to prevent morbidity at instrumental delivery., BMC Pregnancy Childbirth, 2012, 12, 95, doi: 10.1186/1471-2393-12-95.