A weighty issue: The implications of an ultrasound prediction of a large baby in pregnancy

Abstract

Ultrasound scans are an increasingly normalised part of pregnancy in Aotearoa New Zealand. In the third trimester, fetal measurements and weight estimations are undertaken at all scans, regardless of clinical indication. Even though these size predictions can be inaccurate, they heavily influence clinical decision-making. As a result, people with a scan prediction of a large baby may be more likely to have unnecessary interventions that do not improve outcomes, irrespective of the baby’s actual birthweight.

My study aimed to explore the implications of an ultrasound prediction of a large baby on birthing people’s perceptions and experiences of their pregnancies and births, including their birth choices and relationships with caregivers. The study was underpinned by feminist poststructural theory, which is interested in the exposure of apparently fixed truths as socially and politically situated, and the creation of possibility for different ways of knowing and being through the deconstruction of those fixed truths. This focus was consonant with the objectives of my work: to expose the current apparent truths and practices about large babies and birth as the products of dominant medical discourse, and then set about disturbing them and creating space for a midwifery and women-centred narrative of fetal growth.

In conducting the study, I carried out semi-structured interviews with people who had experienced a large baby prediction in pregnancy. I then analysed the data using reflexive thematic analysis. My analysis identified three overarching themes. The first described the two dominant medicalising discourses that prioritised surveillance and risk-centric care, and problematised large babies. The second identified the oppressive effects that engagement with these discourses had, including women experiencing fear, guilt, and a loss of control as they were directed on high intervention care pathways. The third explored the ways that women attempted to resist the oppressive effects of dominant discourse by privileging women’s ways of knowing, trusting their bodies to grow and birth normally, and seeking to gain control of decision-making about their experience. My findings demonstrated the negative impact that a large baby prediction had on women’s experiences and care pathways and identified opportunities for those women to challenge the problematisation of predicted large babies. The importance of a supportive midwifery relationship to these resistances was clear. The role of midwives in partnering with women to challenge medical meanings and practices related to large babies is affirmed as a key finding in this research.