Using intercostal muscle EMG to quantify maternal expulsive efforts during vaginal delivery: A pilot study

Aims: The expulsive forces of childbirth can be included among the many potential risk factors implicated in the subsequent development of stress urinary incontinence (SUI) in women. The objective of this study was to devise a non-invasive way to measure abdominal pushing that would accurately represent the expulsive forces during childbirth. Methods: By means of intravesical and intrauterine manometry, and electromyography (EMG) of intercostal muscles, we quantified these forces in 21 women during vaginal delivery. Results: A mathematical analysis of variance (ANOVA) model showed the integral of intravesical pressure to be significantly associated (P < 0.001) with the integral of intercostal muscle electrical activity during the first six uterine contractions during the phase of fetal expulsion. Conclusions: EMG is a non-invasive measurement that can replace intravesical determinations to quantify these forces as it reflects the real intra-abdominal pressure. (C) 2004 Wiley-Liss, Inc.