The muscle injury nobody mentions
Levator avulsion, and what it predicts.
The levator ani is the sheet of muscle that supports the pelvic organs. In birth it can tear away from the pubic bone. This is not visible and is not detected by any routine examination.
Across 37 studies and 5,594 women, the rate of avulsion by mode of birth was:
| Mode of birth | Levator avulsion |
|---|---|
| Cesarean | 1% |
| Spontaneous vaginal | 15% |
| Vacuum | 21% |
| Forceps | 52% |
It matters because of what follows. In a study of 781 women attending a urogynaecology clinic, significant prolapse was present in 83% of those with avulsion against 44% without, a relative risk of 1.9.
Read the forceps rowRoughly half of forceps deliveries in these studies were associated with this muscle injury. That is not a reason to refuse forceps, which are often the safer alternative to a cesarean with the baby's head deep in the pelvis. It is a reason to be told.
Where this comes from:
220. Rusavy Z, Paymova L, Kozerovsky M, Veverkova A, Kalis V, Kamel RA, et al. Levator ani avulsion: a systematic evidence review (LASER). BJOG. 2022;129(4):517-528.
221. Dietz HP, Simpson JM. Levator trauma is associated with pelvic organ prolapse. BJOG. 2008;115(8):979-984.
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This page is educational. It supports the conversation with your own clinicians. It is not consent to any treatment, and it cannot assess you. If you are worried about a symptom now, see urgent warning signs.