High Incidence of Obstetric Anal Sphincter Injuries among Immigrant Women of Asian Ethnicity

(1) Background: Obstetric anal sphincter injuries (OASI) may complicate vaginal deliveries. The aim of the present study was to explore the incidence and clinical characteristics of OASI among Asian women living in a Western country compared to local Caucasian women. (2) Methods: A retrospective cohort study of 380 women diagnosed with OASI, following singleton vaginal deliveries, during a 10-year period (January 2011 to December 2020). Exclusion criteria: age < 18 years, stillbirth, and breech presentation. Demographic, clinical, and obstetrical data were obtained, and a comparison between Asian and Caucasian women was performed. (3) Results: There were 35 cases of OASI among 997 women of Asian ethnicity compared to 345 cases of OASI among 86,250 Caucasian women (3.5% vs. 0.4%, respectively, p < 0.001). Asian women endured a significantly higher rate of fourth-degree OASI (17.1%) even though they bore smaller newborns (3318 g vs. 3501 g, p = 0.004), and birth weights rarely exceeded 3800 g (2.8% vs. 25.8%, p < 0.001). Asian ethnicity was also associated with a significantly higher risk for blood transfusion following OASI and a lower tendency for postpartum follow up. (4) Conclusions: Immigrant women of Asian ethnicity had a nine-fold higher rate of OASI, much higher than previously reported. Furthermore, Asian women had higher rates of fourth-degree OASI.