AIMS: Our objective was to investigate long-term association between delivery mode, LAM avulsion and obstetric anal sphincter injuries (OASIS) in women at least 20 years after their first birth.

METHODS: All women recruited at 'index birth' of the Dunedin (New Zealand) arm of ProLong (PROlapse and incontinence LONG-term research) Study, were invited to have translabial and transperineal ultrasound assessment of LAM and anal sphincters. Post-processing analysis of imaging data was performed blinded against delivery data. Statistical analysis was performed using the χ2 test and results are expressed as odds ratios (OR).

RESULTS: Of the initial 1250 participants, 196 women returned for examination. Mean age was 50.8 years with a mean body mass index of 27.6 and median parity was three. They were seen on average 23 years after their first delivery. Four data sets were unavailable and one declined ultrasound assessment, leaving 191 for analysis. LAM avulsion was diagnosed in 29 (15.2%), and 24 women (12.6%) had significant anal sphincter defect. LAM avulsion was associated with forceps delivery (OR 2.45, 95% CI 1.04-5.80, P = 0.041). Forceps conveyed a greater risk of OASIS (21%) compared to a spontaneous vaginal delivery (11%) but did not reach statistical significance.

DESIGN: Retrospective observational study.

POPULATION: A total of 1258 consecutive women attending a tertiary urogynaecological unit for the investigation of lower urinary tract or pelvic floor disorders between January 2012 and December 2014.

METHODS: Obstetric history and clinical examination data were obtained from the unit database. Prolapse quantification on imaging was performed using stored four-dimensional translabial ultrasound volume data sets. Women were grouped into four groups according to the most traumatic delivery reported. The presence of symptoms and signs of POP were compared between delivery groups while controlling for potential confounders.

MAIN OUTCOME MEASURES: Prolapse symptoms, visual analogue score for prolapse bother, International Continence Society Prolapse Quantification System findings and ultrasound findings of anterior, central and posterior compartment descent.

RESULTS: Nulliparae showed the lowest prevalence of most measures of POP, followed by women exclusively delivered by caesarean section. Highest prevalences were consistently found in women delivered at least once by forceps, although the differences between this group and women delivered by normal vaginal delivery and/or vacuum extraction were significant in three out of eight measures only. Compared with women in the caesarean section group, the adjusted odds ratios for reporting symptoms of prolapse were 2.4 (95% CI 1.30-4.59) and 3.2 (95% CI 1.65-6.12) in the normal vaginal delivery/vacuum extraction group and forceps group, respectively.

CONCLUSIONS: There is a clear link between vaginal delivery and symptoms and signs of pelvic organ prolapse in urogynaecological patients.

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.