Objective: To evaluate factors associated with subgaleal hemorrhage (SGH) severity following attempted vacuum-assisted delivery (VAD). Study design: This retrospective cohort study was conducted in a tertiary medical center. The population comprised parturients who delivered at our medical center during 2009-2018, and who underwent attempted VAD with singleton pregnancies that resulted in neonatal SGH formation. SGH severity was classified as mild and non-mild (moderate or severe). The main outcome measures were determinants associated with SGH severity. Results: Among 350 neonates with SGH, the degree of severity was non-mild for 48 (13.7%). Compared to the mild group, in the non-mild group, small for gestational age was more common (8.2% vs. 2.6%, p = 0.04). Compared to the mothers in the mild group, in the non-mild group, the proportion with two or more deliveries was lower (0% vs. 7.3%, p = 0.05), gestational diabetes was more common (12.5% vs. 4.6%, p = 0.02), the rate of cervical ripening was higher (27.1% vs. 12.9%, p = 0.02), the duration of the second stage of delivery was longer (mean 177 vs. 152 min, p = 0.04), and the rate of two dislodgments was higher (31.2% vs. 15.2%, p = 0.006). On multivariate analysis, only cervical ripening (adjusted odds ratio [OR]: 2.50; 95% confidence interval [CI]: 1.20-5.26; P = 0.01 and second stage duration (adjusted OR: 1.13; 95% [CI] 1.00-1.29; P = 0.05) were independently associated with more severe SGH. Conclusions: The duration of second stage and ripening of the cervix during induction of labor are independently associated with SGH severity following attempted VAD. (C) 2019 Elsevier B.V. All rights reserved.