Determinants of vaginal-perineal integrity and pelvic floor functioning in childbirth, , ,

OBJECTIVES: Our purpose was to evaluate risk factors for severe vaginal-perineal trauma and to ascertain determinants of pelvic floor strength. STUDY DESIGN: Secondary analysis of 459 nulliparous women enrolled in a randomized controlled trial of episiotomy was carried out. In a multivariate analysis we examined the association between (1) sulcus tears, (2) third- or fourth-degree tears, and (3) pelvic floor strength and selected demographic, physiologic, pregnancy-related, and intrapartum factors. RESULTS: Unemployment and shorter second stage of labor were significant predictors of sulcus tears. Episiotomy, forceps use, and birth weight were important predictors of third- and fourth-degree tears. Whereas perineal intactness (use of episiotomy and spontaneous tears) was not influenced by exercise, a strong exercise profile was associated with fewer third- and fourth-degree tears in the presence of episiotomy. Exercise did not influence the rate of sulcus tears. A total of 35% of the variability in postpartum pelvic floor strength was explained by antepartum strength; however, we were only able to identify 5% of the factors contributing to antepartum pelvic floor strength. CONCLUSIONS: Determinants of sulcus tears appear to be present before pregnancy; third- and fourth-degree tears are related to physician management. Exercise mitigates the potential for severe trauma induced by episiotomy.(Am J Obstet Gynecol 1997;176:403-10.)