Risk factors associated with third- and fourth-degree perineal lacerations in singleton vaginal deliveries: a comprehensive United States population analysis 2016-2020.

We identified several maternal, fetal, and pregnancy conditions that are associated with an increased risk for 3/4PL. As expected, nulliparity and increased birth weight were associated with the highest risk. Moreover, pregestational and gestational diabetes, hypertensive disorders of pregnancy, Asian/Pacific Islander race, and chorioamnionitis were identified as novel risk factors.