Objectives: To review the literature regarding the effects of childbirth on the muscles, nerves, and connective tissue of the pelvic floor, review the evidence to support an association between childbirth and anal incontinence, urinary incontinence, and pelvic organ prolapse; and present recommendations for the prevention of these sequelae.
Data sources: Sources were identified from a MEDLINE search of English-language articles published from 1984 to 1995. Additional sources were identified from references cited in relevant research articles.
Methods of study selection: We studied articles on the following topics: anatomy of the pelvic floor association of childbirth with neuromuscular injury, biomechanical and morphologic alterations in muscle function, and connective tissue structure and function; the long-term effects of childbirth on continence and pelvic organ support; and the effects of obstetric interventions on the pelvic floor.
Tabulation, integration, and results: Articles were reviewed and summarized. An overview of the structure and function of the pelvic floor was developed to provide a context for subsequent data. Childbirth was found to be associated with a variety of muscular and neuromuscular injuries of the pelvic floor that are linked to the development of anal incontinence, urinary incontinence, and pelvic organ prolapse. Risk factors for pelvic floor injury include forceps delivery, episiotomy, prolonged second-stage of labor, and increased fetal size. Cesarean delivery appears to be protective, especially if the patient does not labor before delivery.
Conclusion: The pelvic floor plays an important role in continence and pelvic organ support. Obstetricians may be able to reduce pelvic floor injuries by minimizing forceps deliveries and episiotomies, by allowing passive descent in the second stage, and by selectively recommending elective cesarean delivery.