Background: The hip trial aimed to assess clinical effectiveness, economic and psychosocial costs, and benefits of ultrasound imaging (US) compared with conve ntional clinical assessment alone to guide the management of infants with neonat al hip instability. Objective: To report on psychosocial consequences formothers and the developingmother-child relations hip of US, and associations between abduction splinting and maternal psychosocia l distress. Design: Multicentre randomised controlled trial. Setting: Thirty thr ee hospitals in the United Kingdom and Ireland. Participants, interventions: A t otal of 629 infants with neonatal hip instability randomised to US examination o r clinical assessment alone before treatment decision. Questionnaires were compl eted by 561 (89%) mothers at 8 weeks and 494 (79%) at 1 year. Main outcome mea sures: Anxiety, postnatal depression, parenting stress assessed by standardised questionnaires. Maternal concerns about hip problems were assessed using the Inf ant hip worries inventory. Results: At 8 weeks, there were no differences betwee n US and non-US groups of the trial in maternal anxiety (mean difference (MD)- 1.2, 95%confidence interval (CI)-3.2 to 0.8), depression (MD 0.0, 95%CI- 0.7 to 0.8), parenting stress (MD-1.2, 95%CI-2.8 to 0.4), or other measu res. The same pattern was evident at 1 year. In an explanatory analysis, early s plinting was associated with increased anxiety at 8 weeks (MD 3.8, 95%CI 1.7 to 5.9) and increased level of hip worries at 8 weeks (MD 6.8, 95%CI 5.6 to 7.9) and 1 year (MD 1.3, 95%CI 0.3 to 2.4). Conclusions: Although early spl inting is associated with maternal anxieties, US is not associated with any incr ease or reduction in psychosocial effects on mothers. Together with the clinical findings, this suggests that the use of US allows reduction in splinting rates without increased risk of adverse clinical or psychosocial outcomes. Background: The hip trial aimed to assess clinical effectiveness, economic and psychosocial costs, and benefits of ultrasound imaging (US) compared with conve ntional clinical assessment alone to guide the management of infants with neonat al hip instability. Objective: To report on psychosocial consequences formothers and the developingmother-child relations hip of US, and associations between abduction splinting and maternal psychosocial distress. Design: Multicentre randomized controlled trial. Setting: Thirty thr ee hospitals in the United Kingdom and Ireland. Participants, interventions: A total of 629 infants with neonatal hip instability randomized to US examination or clinical assessment alone before treatment decision. Questionnaires were compl eted by 561 (89%) mothers at 8 weeks and 494 (79%) at 1 year. Main outcome mea sures: Anxiety, postnatal depression, parenting stress assessed by standardized questionnaires. Maternal concerns about hip problems were assessed using t Results: At 8 weeks, there were no differences betwee n US and non-US groups of the trial in maternal anxiety (mean difference (MD) - 1.2, 95% confidence interval (CI) -3.2 to (MD 0.0, 95% CI-0.7 to 0.8), parenting stress (MD-1.2, 95% CI -2.8 to 0.4), or other measu res. The same pattern was evident at 1 year. analysis, early s plinting was associated with increased anxiety at 8 weeks (MD 3.8, 95% CI 1.7 to 5.9) and increased level of hip worries at 8 weeks (MD 6.8, 95% CI 5.6 to 7.9) and 1 year , 95% CI 0.3 to 2.4). Conclusions: Although early spliting is associated with maternal anxieties, US is not associated with any incr ease or reduction in psychosocial effects on mothers. Together with the clinical findings, this suggests that the use of US allows reduction in splinting rates without increased risk of adverse clinical or psychosocial outcomes.