Objective: The purpose of this article is to characterize pelvic floor injury after vaginal childbirth with serial MRI.
Subjects and methods: MR images (3-T) were obtained early (1 month) and late (7 months) after first childbirth in 19 women with risk factors for pelvic floor injury. All women underwent multiplanar intermediate-weighted sequences, and 11 women underwent fluid-sensitive sequences. MR images were evaluated for levator edema and tears and for pubic abnormalities.
Results: Three women had unilateral high-grade tears, three had unilateral low-grade tears, and one had bilateral high- and low-grade tears of the levator ani muscles. All tears were focal at the pubis. Levator edema was present in all women on initial imaging and was resolved at follow-up. Six women had bone marrow edema, five with fracture line. None showed a pattern indicating nerve damage separate from muscle tears.
Conclusion: MRI showed focal levator ani muscle tears at the pubis with bone marrow edema and fracture in patients at risk for pelvic floor injury.