METHODS: This was a cross-sectional study involving 195 women, participants of the Dunedin arm of the ProLong study (PROlapse and incontinence LONG-term research study) seen 20 years after their index birth. Assessment included a standardized questionnaire, ICS POP-Q and 4D translabial ultrasound. Post-imaging analysis of LAM and EAS integrity was undertaken blinded against other data. Statistical analysis was performed using Fisher's exact test and results were expressed as odds ratios (OR).
RESULTS: LAM avulsion and EAS defects were diagnosed in 31 (16%) and 24 (12.4%) women respectively. No significant difference in the prevalence of levator avulsion and EAS defects between primiparous (VP1) and multiparous (VP2+) women who had delivered vaginally (OR 1.9, 95% CI 0.72-5.01, p = 0.26) and (OR 1.2, 95% CI 0.4-3.8, p = 0.76) respectively.
CONCLUSIONS: Most LAM avulsions and EAS defects seem to be caused by the first vaginal birth. Subsequent vaginal deliveries after the first were unlikely to cause further LAM trauma.