[Recording expulsive forces during childbirth using intercostal muscle electromyogram: a pilot study].
OBJECTIVE: The expulsive forces of childbirth can be included among the many potential risk factors implicated in the subsequent development of perineal disorders. 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. PATIENTS AND 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 mixed Ancova 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 6 uterine contractions during the phase of fetal expulsion. DISCUSSION AND CONCLUSION: Electromyography is a non-invasive measurement that can replace intravesical determinations to quantify these forces as it reflects the real intra-abdominal pressure.