Midline Angle as a Predictor of Neonatal Orbital Compression During Forceps Delivery in Occiput Anterior Presentations

AIM: To evaluate the association between intrapartum transperineal ultrasonography findings obtained before forceps delivery and neonatal periorbital compression marks in occiput anterior presentations. METHODS: This retrospective observational study included 166 term singleton forceps deliveries performed at the University of Tokyo Hospital between January 2019 and December 2022. Pregnancies with a non-cephalic presentation, congenital anomalies, or occiput posterior or transverse positions were excluded. Maternal and neonatal characteristics, together with intrapartum transperineal ultrasound findings, including the angle of progression and the midline angle retrospectively measured from ultrasound images acquired immediately before forceps delivery, were compared between neonates with periorbital forceps compression marks and those without compression marks. All neonates in the compression mark group underwent ophthalmologic evaluation. RESULTS: The median midline angle was significantly greater in the compression mark group than in the control group (22.0° vs. 13.0°, p < 0.001). No significant differences were observed between the two groups in maternal or neonatal characteristics or in the angle of progression. The cutoff value of 22° yielded a sensitivity of 47.8% and a specificity of 90.9% for predicting forceps-related compression marks. Nine of the 67 neonates with compression marks had confirmed ophthalmic findings: retinal hemorrhage (n = 1), corneal epithelial injury (n = 2), and subconjunctival hemorrhage (n = 6). All findings resolved spontaneously without intervention. CONCLUSIONS: A midline angle of > 22° was associated with an increased likelihood of periorbital compression during forceps delivery in occiput anterior presentations. Midline angle assessment may be a useful adjunctive parameter for assessing the risk of periorbital compression marks.