Rate of Vaginal Delivery in Relation to the Occiput – Spine Angle and Head – Perineum Distance Measured by Ultrasound During the Second Stage of Labor and Associated Factors at Hung Vuong Hospital. pntmj [Internet]. 2026 Oct. 20 [cited 2026 Nov. 1];5(4). Available from: https://bsgdtphcm.vn/ojs/index.php/pnt/article/view/203