Instrumental delivery and ultrasound: a multicentre randomised controlled trial of ultrasound assessment of the fetal head position versus standard care as an approach to prevent morbidity at instrumental delivery

Objectives: To determine whether the use of ultrasound can reduce the incidence of incorrect diagnosis of the fetal head position at instrumental delivery and subsequent morbidity.Design: Two-arm, parallel, randomised trial, conducted from June 2011 to December 2012.Setting: Two maternity hospitals in the Republic of Ireland.Sample: 514 nulliparous women at term (≥37 weeks' gestation) with singleton cephalic pregnancies, aiming to deliver vaginally were recruited prior to induction of labour or in early labour.Methods: If instrumental delivery was required, women who had provided written consent were randomised to receive clinical assessment (standard care) or ultrasound scan and ultrasound assessment (ultrasound).Main outcome: Incorrect diagnosis of the fetal head position.Results: The incidence of incorrect diagnosis was significantly lower in the ultrasound group than the standard care group (4/257, 1.6% versus 52/257, 20.2%, odds ratio 0.06, 95% confidence interval (CI) 0.02 to 0.19, p valu