Study Identifies Key Risk Factors for Severe Perineal Tears in First-Time Mothers

A large California cohort study found that operative vaginal delivery, particularly forceps, greatly increases the risk of obstetric anal sphincter injury (OASI) in first-time mothers. Asian women had nearly double the risk compared to non-Hispanic white women, while Black and Hispanic women had lower risks. Other factors like maternal diabetes and large-for-gestational-age infants also raised risk, while pre-pregnancy obesity was associated with lower risk.

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The study drew on California birth certificate data linked to hospital discharge records, covering all nulliparous women with singleton, full-term pregnancies delivering live infants between 2016 and 2021. Researchers examined maternal age, self-reported race and ethnicity, education, insurance type, birth attendant, gestational age, and birth weight. Findings appeared in JAMA Network Open.

OASI affects roughly 216,000 American women annually and frequently leads to lasting pelvic floor problems, including prolapse, urinary incontinence, and overactive bladder. About 30% of affected