When does fetal head rotation occur in spontaneous labor at term: results of an ultrasound-based longitudinal study in nulliparous women.

• Published in: American Journal of Obstetrics and Gynecology
• Main Authors: Hjartardóttir, Hulda, Lund, Sigrún H, Benediktsdóttir, Sigurlaug, Geirsson, Reynir T, Eggebø, Torbjørn M
• Other Authors: 1Department of Obstetrics and Gynecology, Landspitali - The National University Hospital of Iceland, Reykjavík, Iceland; Faculty of Medicine, University of Iceland, Reykjavík, Iceland. Electronic address: [e-mail]. 2deCODE genetics, Reykjavík, Iceland. 3Department of Obstetrics and Gynecology, Landspitali - The National University Hospital of Iceland, Reykjavík, Iceland; Faculty of Medicine, University of Iceland, Reykjavík, Iceland. 4National Center for Fetal Medicine, St. Olav's Hospital, Trondheim University Hospital, Trondheim, Norway; Department of Obstetrics and Gynecology, Stavanger University Hospital, Stavanger, Norway; Institute of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2021
• Subjects: active phase; angle of progression; cesarean delivery; fetal head position; head-perineum distance; progress of labor; transabdominal ultrasound; transperineal ultrasound; Fæðing; Labor Presentation; Labor; Obstetric; Reykjavík; Iceland
• Online Access: http://hdl.handle.net/2336/621868; https://doi.org/10.1016/j.ajog.2020.10.054

To access publisher's full text version of this article click on the hyperlink below Background: Improved information about the evolution of fetal head rotation during labor is required. Ultrasound methods have the potential to provide reliable new knowledge about fetal head position. Objective: The aim of the study was to describe fetal head rotation in women in spontaneous labor at term using ultrasound longitudinally throughout the active phase. Study design: This was a single center, prospective cohort study at Landspitali - The National University Hospital of Iceland, Reykjavík, Iceland, from January 2016 to April 2018. Nulliparous women with a single fetus in cephalic presentation and spontaneous labor onset at ≥37 weeks' gestation were eligible. Inclusion occurred when the active phase could be clinically established by labor ward staff. Cervical dilatation was clinically examined. Fetal head position and subsequent rotation were determined using both transabdominal and transperineal ultrasound. Occiput positions were marked on a clockface graph with 24 half-hour divisions and categorized into occiput anterior (≥10- and ≤2-o'clock positions), left occiput transverse (>2- and <4-o'clock positions), occiput posterior (≥4- and ≤8 o'clock positions), and right occiput transverse positions (>8- and <10-o'clock positions). Head descent was measured with ultrasound as head-perineum distance and angle of progression. Clinical vaginal and ultrasound examinations were performed by separate examiners not revealing the results to each other. Results: We followed the fetal head rotation relative to the initial position in the pelvis in 99 women, of whom 75 delivered spontaneously, 16 with instrumental assistance, and 8 needed cesarean delivery. At inclusion, the cervix was dilated 4 cm in 26 women, 5 cm in 30 women, and ≥6 cm in 43 women. Furthermore, 4 women were examined once, 93 women twice, 60 women 3 times, 47 women 4 times, 20 women 5 times, 15 women 6 times, and 3 women 8 times. Occiput posterior ...