Ultrasound examination of the pelvic floor during active labor: A longitudinal cohort study
Abstract 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,...
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Wiley
2023-09-01
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| Series: | Acta Obstetricia et Gynecologica Scandinavica |
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| Online Access: | https://doi.org/10.1111/aogs.14620 |
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| author | Torbjørn M. Eggebø Sigurlaug Benediktsdottir Hulda Hjartardottir Kjell Å. Salvesen Ingrid Volløyhaug |
| author_facet | Torbjørn M. Eggebø Sigurlaug Benediktsdottir Hulda Hjartardottir Kjell Å. Salvesen Ingrid Volløyhaug |
| author_sort | Torbjørn M. Eggebø |
| collection | DOAJ |
| description | Abstract 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, r2 = 0.19; p < 0.01; regression equation y = 2.71 + 0.014x), and a weak correlation between the change in transverse hiatal diameter and change in fetal station (r = 0.29; r2 = 0.08; p = 0.01; regression equation y = 0.24 + 0.012x). Levator urethral gap increased significantly in all three planes on both the left and right sides. Head position was not associated with hiatal measurements after adjusting for fetal station. Conclusions We found a significant, but only modest, increase of the hiatal dimensions during the first stage of labor. The risk of levator ani trauma will therefore be low during this stage. The change in transverse hiatal diameter was associated with fetal descent but not with head position. |
| format | Article |
| id | doaj-art-0f38a623fac54b518e6a852ffa689d68 |
| institution | DOAJ |
| issn | 0001-6349 1600-0412 |
| language | English |
| publishDate | 2023-09-01 |
| publisher | Wiley |
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| series | Acta Obstetricia et Gynecologica Scandinavica |
| spelling | doaj-art-0f38a623fac54b518e6a852ffa689d682025-08-20T03:22:26ZengWileyActa Obstetricia et Gynecologica Scandinavica0001-63491600-04122023-09-0110291203120910.1111/aogs.14620Ultrasound examination of the pelvic floor during active labor: A longitudinal cohort studyTorbjørn M. Eggebø0Sigurlaug Benediktsdottir1Hulda Hjartardottir2Kjell Å. Salvesen3Ingrid Volløyhaug4National Center for Fetal Medicine Trondheim University Hospital (St. Olavs Hospital) Trondheim NorwayDepartment of Obstetrics and Gynecology Landspitali University Hospital Reykjavik IcelandDepartment of Obstetrics and Gynecology Landspitali University Hospital Reykjavik IcelandNational Center for Fetal Medicine Trondheim University Hospital (St. Olavs Hospital) Trondheim NorwayInstitute of Clinical and Molecular Medicine Norwegian University of Science and Technology Trondheim NorwayAbstract 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, r2 = 0.19; p < 0.01; regression equation y = 2.71 + 0.014x), and a weak correlation between the change in transverse hiatal diameter and change in fetal station (r = 0.29; r2 = 0.08; p = 0.01; regression equation y = 0.24 + 0.012x). Levator urethral gap increased significantly in all three planes on both the left and right sides. Head position was not associated with hiatal measurements after adjusting for fetal station. Conclusions We found a significant, but only modest, increase of the hiatal dimensions during the first stage of labor. The risk of levator ani trauma will therefore be low during this stage. The change in transverse hiatal diameter was associated with fetal descent but not with head position.https://doi.org/10.1111/aogs.14620birthfetal descenthead positionhiatal dimensionsinjurylabor |
| spellingShingle | Torbjørn M. Eggebø Sigurlaug Benediktsdottir Hulda Hjartardottir Kjell Å. Salvesen Ingrid Volløyhaug Ultrasound examination of the pelvic floor during active labor: A longitudinal cohort study Acta Obstetricia et Gynecologica Scandinavica birth fetal descent head position hiatal dimensions injury labor |
| title | Ultrasound examination of the pelvic floor during active labor: A longitudinal cohort study |
| title_full | Ultrasound examination of the pelvic floor during active labor: A longitudinal cohort study |
| title_fullStr | Ultrasound examination of the pelvic floor during active labor: A longitudinal cohort study |
| title_full_unstemmed | Ultrasound examination of the pelvic floor during active labor: A longitudinal cohort study |
| title_short | Ultrasound examination of the pelvic floor during active labor: A longitudinal cohort study |
| title_sort | ultrasound examination of the pelvic floor during active labor a longitudinal cohort study |
| topic | birth fetal descent head position hiatal dimensions injury labor |
| url | https://doi.org/10.1111/aogs.14620 |
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