BACKGROUND: Obstetrical levator ani muscle avulsion is detected after 10-30% of vaginal deliveries and is associated with pelvic organ prolapse later in life. However, the mechanism by which levator avulsion may contribute to prolapse is unknown. OBJECTIVES:This study investigated the extent by which size of the levator hiatus and pelvic muscle weakness may explain the association between levator avulsion and pelvic organ prolapse. STUDY DESIGN:This was a supplementary study of a longitudinal cohort of parous women enrolled 5-10 years after first delivery and assessed annually for prolapse (defined as descent beyond the hymen) for up to 9 annual visits. For this sub-study, vaginally parous participants were assessed for levator avulsion using 3dimensional transperineal ultrasound. Ultrasound was performed at a median interval of 11 years from delivery. Ultrasound volumes were also used to measure levator hiatus area with Valsalva. Pelvic muscle strength was measured with perineometry. Women with and without pelvic organ prolapse were compared for levator avulsion, levator hiatus area, and pelvic muscle strength, using multivariable logistic regression yielding a measure of mediation. Bootstrap methods were used to calculate the confidence interval corresponding to the measure of mediation by hiatus area and pelvic muscle strength.

Objectives With vaginal childbirth, 10% to 30% of women sustain levator ani muscle avulsion. The objective of this study was to estimate the cumulative incidence of prolapse and other pelvic floor disorders (PFDs), comparing vaginally parous women with and without levator avulsion. Methods Parous women enrolled in a longitudinal study were assessed annually for PFDs with the Pelvic Organ Prolapse Quantification Examination (for prolapse) and the Epidemiology of Prolapse and Incontinence Questionnaire (for stress incontinence, overactive bladder, and anal incontinence). Three-dimensional transperineal ultrasound was used to identify levator avulsion. Women with and without levator avulsion after vaginal delivery were compared for the cumulative incidence of PFDs. Further analysis also stratified by forceps delivery. Results At the time of assessment, 453 participants were 6 to 17 years from first delivery (median, 11 years). Levator avulsion was identified in 15% (66/453) and was more common among those who had undergone forceps-assisted delivery (P < 0.001). Levator avulsion was strongly associated with prolapse beyond the hymen (odds ratio, 2.7; 95% confidence interval, 1.3–5.7) and with symptoms of prolapse (odds ratio, 3.0; 95% confidence interval–1.2, 7.3). These associations persisted after controlling for forceps-assisted delivery. In contrast, the odds of stress incontinence, overactive bladder, and anal incontinence were marginally (but not significantly) increased among women with levator avulsion in this cohort. Conclusions Obstetric levator avulsion is strongly associated with pelvic organ prolapse. The relationship between levator avulsion and other PFDs may not be significant.

Background and objectivesStudies of adults have demonstrated an association between metabolic acidosis, as measured by low serum bicarbonate levels, and CKD progression. We evaluated this relationship in children using data from the Chronic Kidney Disease in Children study.Design, setting, participants, & measurementsThe relationship between serum bicarbonate and a composite end point, defined as 50% decline in eGFR or KRT, was described using parametric and semiparametric survival methods. Analyses were stratified by underlying nonglomerular and glomerular diagnoses, and adjusted for demographic characteristics, eGFR, proteinuria, anemia, phosphate, hypertension, and alkali therapy.ResultsSix hundred and three participants with nonglomerular disease contributed 2673 person-years of follow-up, and 255 with a glomerular diagnosis contributed 808 person-years of follow-up. At baseline, 39% (237 of 603) of participants with nonglomerular disease had a bicarbonate level of ≤22 meq/L and 36% (85 of 237) of those participants reported alkali therapy treatment. In participants with glomerular disease, 31% (79 of 255) had a bicarbonate of ≤22 meq/L, 18% (14 of 79) of those participants reported alkali therapy treatment. In adjusted longitudinal analyses, compared with participants with a bicarbonate level >22 meq/L, hazard ratios associated with a bicarbonate level of <18 meq/L and 19–22 meq/L were 1.28 [95% confidence interval (95% CI), 0.84 to 1.94] and 0.91 (95% CI, 0.65 to 1.26), respectively, in children with nonglomerular disease. In children with glomerular disease, adjusted hazard ratios associated with bicarbonate level ≤18 meq/L and bicarbonate 19–22 meq/L were 2.16 (95% CI, 1.05 to 4.44) and 1.74 (95% CI, 1.07 to 2.85), respectively. Resolution of low bicarbonate was associated with a lower risk of CKD progression compared with persistently low bicarbonate (≤22 meq/L).ConclusionsIn children with glomerular disease, low bicarbonate was linked to a higher risk of CKD progression. Resolution of low bicarbonate was associated with a lower risk of CKD progression. Fewer than one half of all children with low bicarbonate reported treatment with alkali therapy. Long-term studies of alkali therapy’s effect in patients with pediatric CKD are needed.

Vaginal birth was associated with worse support 5 years from first delivery and with more rapid deterioration in support at the apex. Above and beyond the impact of vaginal birth, the size of the genital hiatus may be an independent marker for those at greatest risk of prolapse progression.

(Abstracted from Am J Obstet Gynecol 2019;221:41.e1–41.e7) Vaginal childbirth significantly increases the likelihood that a parous woman will develop pelvic organ prolapse (POP). Reasons for the association between vaginal childbirth and POP are unclear, but one postulated mechanism is injury to the obstetrical injury to the levator ani muscles.