Patterns of Labour Interventions and Associated Maternal Biopsychosocial Factors in Australia: a Path Analysis

In Australia, nearly half of births involve labour interventions. Prior research in this area has relied on cross-sectional and administrative health data and has not considered biopsychosocial factors. The current study examined direct and indirect associations between biopsychosocial factors and labour interventions using 19 years of population-based prospective data. The study included singleton babies among primiparous women of the 1973–1978 cohort of the Australian Longitudinal Study on Women’s Health. Data from 5459 women who started labour were analysed using path analysis. 42.2% of babies were born without intervention (episiotomy, instrumental, or caesarean delivery): Thirty-seven percent reported vaginal birth with episiotomy and instrumental birth interventions, 18% reported an unplanned caesarean section without episiotomy and/or instrumental interventions, and 3% reported unplanned caesarean section after episiotomy and/or instrumental interventions. Vaginal births with episiotomy and/or instrumental interventions were more likely among women with chronic hypertension (RRR(95%-CI):1.50(1.12–2.01)), a perceived length of labour of more than 36 h (RRR(95%-CI):1.86(1.45–2.39)), private health insurance (RRR(95%-CI):1.61(1.41–1.85)) and induced labour (RRR(95%-CI):1.69(1.46–1.94)). Risk factors of unplanned caesarean section without episiotomy and/or instrumental birth intervention included being overweight (RRR(95%-CI):1.30(1.07–1.58)) or obese prepregnancy (RRR(95%-CI):1.63(1.28–2.08)), aged ≥ 35 years (RRR(95%-CI):1.87(1.46–2.41)), having short stature (< 154 cm) (RRR(95%-CI):1.68(1.16–2.42)), a perceived length of labour of more than 36 h (RRR(95%-CI):3.26(2.50–4.24)), private health insurance (RRR(95%-CI):1.38(1.17–1.64)), and induced labour (RRR(95%-CI):2.56(2.16–3.05)). Prevention and management of hypertension, diabetes, and obesity during preconception and/or antenatal care are keys for reducing labour interventions and strengthening the evidence-base around delivery of best practice obstetric care.