LATEBREAKER
Health Disparities
Contextualizing racial/ethnic disparities in obstetric anal sphincter injury in the United States Maya Rajasingham* Maya Rajasingham Parnian Hossein-Pour Rohan D’Souza Roxana Geoffrion Cande Ananth Giulia Muraca
Introduction
Racial disparities in obstetric anal sphincter injury (OASI) across parity, mode of delivery, and immigration status are poorly understood; their investigation may provide valuable insight into individuals at greatest risk of OASI.
Methods
We designed a cohort study of 15,964,178 vaginal births in the United States (US) using CDC Natality Files (2016–2021). Cox proportional hazard models, adjusted for confounders with gestational age as the underlying timescale, were fit to evaluate the association between self-reported race/ethnicity and OASI. Models were stratified by parity (nulliparous/parous), obstetric history (previous cesarean delivery), and mode of delivery (spontaneous vaginal [SVD], forceps, vacuum).
Results
In nullipara, OASI rates varied by mode of delivery with the highest rate among forceps (SVD: 2.0%, forceps: 14.7%, vacuum: 6.6%). Non-Hispanic Asian individuals experienced the highest rates of OASI across all modes of delivery. Compared to non-Hispanic White individuals, OASI rates among Asian individuals with SVD were 3.3% vs. 1.9% (aHR 1.66; 95% CI 1.64, 1.67), 21.9% vs. 15.1% with forceps (aHR 1.52; 95% CI 1.48, 1.56), and 10.9% vs. 6.9% with vacuum (aHR 1.54; 95% CI 1.52, 1.57). OASI rates varied between Asian subgroups, with the highest rate in Indian individuals (SVD: 4.1%, forceps: 27.2%, vacuum: 13.1%). Among forceps, higher OASI rates were observed in non-Hispanic Black vs. White individuals (Fig 1). OASI rates were higher among foreign- vs. US-born residents within each race. Similar trends were apparent in the parous population.
Conclusions
In the US, Asian individuals, particularly those who identify as Indian, have higher OASI rates than White individuals, irrespective of parity and mode of delivery. Rates of OASI are higher among foreign-born US residents. These findings underscore the importance of training birth attendants in best practices, and a tailored counselling approach that is culturally sensitive and trauma informed.
