Intrapartum sonographic assessment of the fetal head flexion in protracted active phase of labor and association with labor outcome: a multicenter, prospective study

• Published in: American journal of obstetrics and gynecology 2021-08, Vol.225 (2), p.171.e1-171.e12
• Main Authors: Dall’Asta, Andrea, Rizzo, Giuseppe, Masturzo, Bianca, Di Pasquo, Elvira, Schera, Giovanni Battista Luca, Morganelli, Giovanni, Ramirez Zegarra, Ruben, Maqina, Pavjola, Mappa, Ilenia, Parpinel, Giulia, Attini, Rossella, Roletti, Enrica, Menato, Guido, Frusca, Tiziana, Ghi, Tullio
• Format: Article
• Language: English
• Subjects: Adult; angle of progression; cesarean delivery; Cesarean Section - statistics & numerical data; chin-to-chest angle; Delivery, Obstetric - statistics & numerical data; Dystocia - diagnostic imaging; Dystocia - therapy; Extraction, Obstetrical - statistics & numerical data; Female; Fetus - diagnostic imaging; Head - diagnostic imaging; head-perineum distance; Humans; instrumental delivery; intrapartum care; labor dystocia; Labor Presentation; Labor Stage, First; Logistic Models; Neck - diagnostic imaging; occiput-spine angle; Pregnancy; Spine - diagnostic imaging; Ultrasonography; ultrasound in labor
• ISSN: 0002-9378; 1097-6868
• DOI: 10.1016/j.ajog.2021.02.035

To date, no research has focused on the sonographic quantification of the degree of flexion of the fetal head in relation to the labor outcome in women with protracted active phase of labor. This study aimed to assess the relationship between the transabdominal sonographic indices of fetal head flexion and the mode of delivery in women with protracted active phase of labor. Prospective evaluation of women with protracted active phase of labor recruited across 3 tertiary maternity units. Eligible cases were submitted to transabdominal ultrasound for the evaluation of the fetal head position and flexion, which was measured by means of the occiput-spine angle in fetuses in nonocciput posterior position and by means of the chin-to-chest angle in fetuses in occiput posterior position. The occiput-spine angle and the chin-to-chest angle were compared between women who had vaginal delivery and those who had cesarean delivery. Cases where obstetrical intervention was performed solely based on suspected fetal distress were excluded. A total of 129 women were included, of whom 43 (33.3%) had occiput posterior position. Spontaneous vaginal delivery, instrumental delivery, and cesarean delivery were recorded in 66 (51.2%), 17 (13.1%), and 46 (35.7%) cases, respectively. A wider occiput-spine angle was measured in women who had vaginal delivery compared with those submitted to cesarean delivery owing to labor dystocia (126±14 vs 115±24; P