Author: Siobhan Fitzpatrick
Fitzpatrick, Siobhan, 2025 Rectus diastasis of parity: Incidence, treatment and outcomes, Flinders University, College of Medicine and Public Health
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Rectus diastasis of parity is a frequently overlooked outcome of childbearing, and at the commencement of this PhD, its existence as a discreet pathological entity that can be measured and treated remained unclear. Abdominoplasty surgery to correct rectus diastasis has often been classified as a cosmetic procedure by society, healthcare professionals and policymakers, creating potential barriers to access. This PhD is a comprehensive body of work examining rectus diastasis of parity, specifically investigating its incidence, its impact on women, and determining benefits and cost-effectiveness of treatment with abdominoplasty.
Commencing with a thorough review of the literature (Chapter 1), this thesis identified various limitations in the quality and content of research surrounding rectus diastasis. These gaps subsequently informed a series of research questions, which were systematically answered by the five studies of this thesis, ensuring an original contribution to knowledge.
The qualitative study described in Chapter 2, aimed to elucidate the experiences of Australian women living with rectus diastasis of parity, to facilitate the development of a definition and understanding that is useful to policymakers, fiscal experts, medical practitioners, and women who live with the condition. Using qualitative content analysis various key themes were identified which were shared between the women, including impaired physical function, back pain, and poor mental health. Unique to this analysis was the impact that the removal of government funding for abdominoplasty surgery had on the lived experiences of these women. The funding decision had impacted their experience of rectus diastasis, the way that society and health professionals viewed them, and their ability to access treatment.
The three quantitative studies of Chapters 3, 4, and 5, relied on patient reported outcome measures completed by three distinct populations of women, to characterise the natural history and impact of rectus diastasis. Chapter 3 examined the health-related quality of life, back pain, and urinary incontinence of women without rectus diastasis, who would ultimately form a reference population of women. These women had low levels of back pain and urinary incontinence, and high levels of health-related quality of life.
Chapter 4 prospectively investigated the health-related quality of life, back pain, and urinary incontinence of women from early pregnancy until 12-months postpartum, relating these outcomes to their inter-rectus distances, as measured with ultrasound, to determine which women developed what would newly be referred to as Symptomatic Established Rectus Diastasis (SERD) at the study end point. The proportion of women with SERD at 12-months postpartum was one in four, and they had significantly impaired health-related quality of life compared to women without SERD. Risk factors identified included gestational diabetes, lower maternal BMI, and higher total foetal birthweight.
Chapter 5 prospectively examined the health-related quality of life, back pain, urinary incontinence, and body-image of women with SERD undergoing abdominoplasty. At baseline, women with SERD had significantly impaired outcomes compared to the reference population of women. Surgery resulted in statistically and clinically meaningful improvements in these outcomes, to the level of women without rectus diastasis and normative populations of women. These improvements were sustained at 12-months follow-up. Contrastingly, the cohort of women with SERD who did not undergo surgery demonstrated no change in any outcomes measured during the 12-months of follow-up.
The economic evaluation featured in Chapter 6 transformed the health-related quality of life data collected in this body of work into preference-based utility scores. The subsequent cost-utility analysis performed found abdominoplasty to be a cost-effective intervention that warrants ongoing funding in the Australian healthcare system.
The concluding chapter (Chapter 7) summarises the findings of this thesis and their impact. Ultimately, this body of work provides significant evidence that Symptomatic Established Rectus Diastasis is a discreet pathological entity that can be measured and treated, and that abdominoplasty repair is a functional, beneficial, and cost-effective operation in the Australian healthcare context.
Keywords: rectus diastasis, women's health, health-related quality of life, back pain, urinary incontinence, abdominoplasty, plastic surgery
Subject: Medicine thesis
Thesis type: Doctor of Philosophy
Completed: 2025
School: College of Medicine and Public Health
Supervisor: Associate Professor Nicola Dean