Ultrasound is a tool of increasing importance in maternity care. Midwives have a central position in the care of pregnant women. However, studies regarding their experiences of the use of ultrasound in this context are limited. The purpose of this study was to explore Australian midwives' experiences and views of the role of obstetric ultrasound particularly in relation to clinical management of complicated pregnancy, and situations where maternal and fetal health interests conflict.A qualitative study was undertaken in Victoria, Australia in 2012, based on six focus group discussions with midwives (n = 37) working in antenatal and intrapartum care, as part of the CROss-Country Ultrasound Study (CROCUS). Data were analysed using qualitative content analysis.One overarching theme emerged from the analysis: Obstetric ultrasound--a routine tool with far-reaching influence, and it was built on three categories. First, the category'Experiencing pros and cons of ultrasound' highlighted that ultrasound was seen as having many advantages; however, it was also seen as contributing to increased medicalisation of pregnancy, to complex and sometimes uncertain decision-making and to parental anxiety. Second, 'Viewing ultrasound as a normalised and unquestioned examination' illuminated how the use of ultrasound has become normalised and unquestioned in health care and in wider society. Midwives were concerned that this impacts negatively on informed consent processes, and at a societal level, to threaten acceptance of human variation and disability. Third, 'Reflecting on the fetus as a person in relation to the pregnant woman' described views on that ultrasound has led to increased 'personification' of the fetus, and that women often put fetal health interests ahead of their own.The results reflect the significant influence ultrasound has had in maternity care and highlights ethical and professional challenges that midwives face in their daily working lives concerning its use. Further discussion about the use of ultrasound is needed, both among health professionals and in the community, in order to protect women's rights to informed decision-making and autonomy in pregnancy and childbirth and to curb unnecessary medicalisation of pregnancy. Midwives' experiences and views play an essential role in such discussions.