Ultrasound examination of the pelvic floor during active labor : A longitudinal cohort study

• Published in: Acta Obstetricia et Gynecologica Scandinavica
• Main Authors: Eggebø, Torbjørn M., Benediktsdóttir, Sigurlaug, Hjartardóttir, Hulda, Salvesen, Kjell, Volløyhaug, Ingrid
• Other Authors: Other departments
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2023
• Subjects: Fæðinga- og kvensjúkdómafræði; birth; fetal descent; head position; hiatal dimensions; injury; labor; levator ani; obstetrics; pelvic floor; prolapse; ultrasound; urogynecology; Prospective Studies; Humans; Infant; Pregnancy; Delivery; Obstetric; Ultrasonography; Female; Pelvic Floor/diagnostic imaging; Imaging; Three-Dimensional; Longitudinal Studies; Obstetrics and Gynecology; Iceland
• Online Access: https://hdl.handle.net/20.500.11815/4419; https://doi.org/10.1111/aogs.14620

Publisher Copyright: © 2023 The Authors. Acta Obstetricia et Gynecologica Scandinavica published by John Wiley & Sons Ltd on behalf of Nordic Federation of Societies of Obstetrics and Gynecology (NFOG). © 2023 The Authors. Acta Obstetricia et Gynecologica Scandinavica published by John Wiley & Sons Ltd on behalf of Nordic Federation of Societies of Obstetrics and Gynecology (NFOG). INTRODUCTION: There is limited evidence about changes in the pelvic floor during active labor. We aimed to investigate changes in hiatal dimensions during the active first stage of labor and associations with fetal descent and head position. MATERIAL AND METHODS: We conducted a longitudinal, prospective cohort study at the National University Hospital of Iceland, from 2016 to 2018. Nulliparous women with spontaneous onset of labor, a single fetus in cephalic presentation, and gestational age ≥37 weeks were eligible. Fetal position was assessed with transabdominal ultrasound and fetal descent was measured with transperineal ultrasound. Three-dimensional volumes were acquired from transperineal scanning at the start of the active phase of labor and in late first stage or early second stage. The largest transverse hiatal diameter was measured in the plane of minimal hiatal dimensions. The levator urethral gap was measured as the distance between the center of the urethra and the levator insertion using tomographic ultrasound imaging. Measurements of the levator urethral gap were made in the plane of minimal hiatal dimensions and 2.5 and 5 mm cranial to this. RESULTS: The final study population comprised 78 women. The mean transverse hiatal diameter increased 12.4% between the two examinations, from 39.4 ± 4.1 mm (±standard deviation) at the first examination to 44.3 ± 5.8 mm at the last examination (p < 0.01). We found a moderate correlation between the transverse hiatal diameter and fetal station at the last examination (r = 0.44, r 2 = 0.19; p < 0.01; regression equation y = 2.71 + 0.014x), and a weak correlation ...