Pelvic floor muscle strength in the postpartum period of women with history of obstetric anal sphincter injuries

Introduction and aim of the study: According with the Green Top Guidelines of the RCOG [[1]Royal College of Obstetricians and Gynaecologists A third-or fourth-degree tear during birth: Information for you. RCOG, London2015Google Scholar], women with history of obstetric anal sphincter injuries (OASIS) should be advised that physiotherapy could be beneficial. The aim of the study was to evaluate the pelvic floor muscles (PFM) strength in the postpartum period of a cohort of women with history of OASIS. Materials and methods: Voluntary PFM contraction and relaxation was evaluated at 6 months postpartum by vaginal palpation, and scored according to the Modified Oxford Grading Scale (MOS) [[2]Laycock J. Clinical evaluation of pelvic floor.in: Schussler B. Laycok J. Norton P. Stanton S. Pelvic floor re-eductio. Principles and practice. Springer-Verlag, London1994: 42-48Google Scholar]. Additionally, MOS score was dichotomized in MOS ≤ 2 (underactive/non-functioning) and MOS ≥ 3 (normal). Results: 95 females with OASIS identified and repaired intrapartum were included. 56 women (59%) presented an underactive/non-functioning PFM. No statistically significant differences were found between these patients and patients with normal PFM, considering newborn weight or degree of OASIS. A higher percentage of patients who delivered with forceps, showed a weak PFM strength, compared with women who delivered spontaneously (p = 0.04). Furthermore, participants who delivered spontaneously presented a higher MOS than those who delivered with forceps (mean value 2.4 ± 1.3 versus 1.9 ± 1.1, respectively; p = 0.04). Considering age, there was a statistically significant negative correlation between ages and MOS score (p = 0.04, Spearman's correlation). No statistically significant differences were observed in MOS when comparing to different degrees of OASIS. Mean and SD for 3a, 3b, 3c and 4 were 2.0 ± 1.3; 2.3 ± 1.2; 2.6 ± 0.9; 2.0 ± 1.4, respectively. Interpretation of results: There is no evidence to indicate the optimal method of follow-up after OASIS. A vaginal examination with a digital palpation could be useful before starting a PFM training program. Patients with an underactive or non-functioning PFM would need a different program. Conclusions: More than a half of patients with history of OASIS showed an underactive or non-functioning PFM at 6 months postpartum. Patients who delivered with forceps presented a lower MOS score.