Pelvic floor after childbirth

It is the last five minutes of a long second stage. The head delivers over a tight perineum with forceps, and as you examine the tear you realise the bleeding is coming from somewhere deeper than the skin. What you do in the next two minutes — the quality of your inspection, your rectal examination, and the accuracy of your grading — decides whether this woman is continent at her next birthday or not. Maternal birth trauma is common, often invisible at the time, and a major cause of pelvic floor dysfunction in young women.^[1][5]

Overview and definition

Maternal birth trauma is the structural and neurological injury the pelvic floor sustains during vaginal birth. It has two anatomical targets and you should hold both in your head at once.^[5][8]

• Levator ani injury — the pubovisceral (puborectalis) muscle is detached from its insertion on the inferior pubic ramus as the fetal head descends and distends the hiatus. A complete detachment is an avulsion; over-stretching without detachment, leaving an enlarged hiatus, is microtrauma (ballooning).^[5][13]
• Anal sphincter injury (OASIS) — disruption of the external anal sphincter (EAS), the internal anal sphincter (IAS), or the anorectal mucosa. Third-degree tears involve the EAS and/or IAS; fourth-degree tears extend through to the epithelium.^[1][2]

The concept that transforms your practice: most significant sphincter injury is occult. The woman is told her perineum is intact when the sphincter is partly torn. These women present months later with faecal urgency, and the damage was done — and missed — at delivery.^[1]

^{[1] [2]}

References14ShowHide

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2. [2]Okeahialam NA, Taithongchai A, Thakar R, Sultan AH The incidence of anal incontinence following obstetric anal sphincter injury graded using the Sultan classification: a network meta-analysis Am J Obstet Gynecol, 2023.PMID 36379266
3. [3]Fernando RJ, Sultan AH, Kettle C, Thakar R Methods of repair for obstetric anal sphincter injury Cochrane Database Syst Rev, 2013.PMID 24318732
4. [4]Sultan A, Fernando R Overlapping compared with end-to-end repair of third- and fourth-degree obstetric anal sphincter tears: a randomized controlled trial Obstet Gynecol, 2011.PMID 21252767
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10. [10]Cacciari LP, Dumoulin C, Hay-Smith EJ Pelvic floor muscle training versus no treatment, or inactive control treatments, for urinary incontinence in women: a cochrane systematic review abridged republication Braz J Phys Ther, 2019.PMID 30704907
11. [11]Sigurdardottir T, Steingrimsdottir T, Geirsson RT, et al. Can postpartum pelvic floor muscle training reduce urinary and anal incontinence?: An assessor-blinded randomized controlled trial Am J Obstet Gynecol, 2020.PMID 31526791
12. [12]Hilde G, Stær-Jensen J, Siafarikas F, et al. Postpartum pelvic floor muscle training and urinary incontinence: a randomized controlled trial Obstet Gynecol, 2013.PMID 24201679
13. [13]Caudwell-Hall J, Kamisan Atan I, Guzman Rojas R, Langer S, Shek KL, Dietz HP Atraumatic normal vaginal delivery: how many women get what they want? Am J Obstet Gynecol, 2018.PMID 30063899
14. [14]de Oliveira Freitas GS, Anzolch MJ, Capp E, Ramos JGL, Picoloto ASB Prevalence of Perineal Injury After First Vaginal Delivery and Its Association With Pregnancy and Birth Characteristics J Obstet Gynaecol Res, 2025.PMID 41355302