Three-dimensional ultrasound imaging of the levator hiatus in late pregnancy and associations with delivery outcomes
Article first published online: 5 JUN 2007
Australian and New Zealand Journal of Obstetrics and Gynaecology
Volume 47, Issue 3, pages 176–180, June 2007
How to Cite
LANZARONE, V. and DIETZ, H. P. (2007), Three-dimensional ultrasound imaging of the levator hiatus in late pregnancy and associations with delivery outcomes. Australian and New Zealand Journal of Obstetrics and Gynaecology, 47: 176–180. doi: 10.1111/j.1479-828X.2007.00714.x
- Issue published online: 5 JUN 2007
- Article first published online: 5 JUN 2007
- Received 14 December 2006; accepted 09 February 2007.
- three-dimensional ultrasound;
- delivery outcomes;
- levator ani muscle;
- pelvic floor
Objective: To determine the correlations between dimensions of the levator hiatus in late pregnant nulliparous women, mode of delivery and length of second stage.
Methods: This was a prospective observational pilot study of 61 nulliparous women seen and examined between 36 and 40 weeks of pregnancy. A translabial ultrasound examination was undertaken, and three-dimensional volumes comprising the levator hiatus were recorded at rest, during a pelvic floor muscle contraction and on Valsalva. The volumes were analysed in a blinded fashion using proprietary software to determine linear dimensions and hiatal area. Information regarding delivery outcomes and course of labour was obtained from the obstetric database. Statistical analysis was undertaken for correlations between hiatal dimensions and labour outcomes.
Results: No consistent correlations were found between levator dimensions and delivery mode. However, an inverse correlation was demonstrated between the area of the hiatus, particularly on pelvic floor contraction, and length of total second stage.
Conclusions: Levator hiatal dimensions are associated with the length of the second stage of labour. Although the numbers were small, our findings suggest that the effect of pelvic floor structures on progress in labour is worth further study.