Obstetric Anal Sphincter Injuries (OASIS)

What is OASIS, and what can you do if you experience it? Let’s dive into this important topic.

Obstetric Anal Sphincter Injuries, or OASIS, is when there is perineal trauma (a tear) during a vaginal delivery. It is classified as OASIS when the degree of perineal trauma is considered a third or fourth degree tear.  

  • A third degree tear involves injury to the perineum and the anal sphincter complex. 
  • A fourth degree perineal tear are is the most severe and involves the entire anal sphincter complex and anal epithelium.

 What is the perineum?

The perineum is the space between the vaginal opening and the rectum, where many of the deep and superficial muscles of the pelvic floor converge on a central tendon. The perineum plays a key role in maintaining the stability of the pelvic floor. When damaged, it can lead to a number of complications, including painful intercourse (dyspareunia), urinary or fecal urgency (intense need to urinate or defecate) and incontinence (the loss of control of the bladder or bowels).

According to the World Health Organization, OASIS occurs in 4 to 7 % of all vaginal births. Assisted deliveries (use of forceps and/or vaccum) increases the risk.

OASIS and sex

OASIS (perineal trauma) can have long-term effects on a woman's life and well-being. The pain associated with OASIS – as well as the associated tension within the pelvic floor muscles – often leads to painful intercourse (called dyspareunia) and an avoidance of sex. There may be embarrassment or shame in even admitting what you’re going through.

If you struggle with OASIS and dyspareunia, know that you’re not alone and there is help available. Speaking to a Pelvic Health Physiotherapist, who sees and treats people with this issue all the time, is a good place to start. A Pelvic Health Physiotherapist works closely with you to understand your pain and guide a comprehensive rehabilitation program with the goals of regaining strength within the perineal area, and relaxing the muscles within the pelvic floor. This is done through a thorough examination in which they will assess your muscle tone by gently pressing on your pelvic floor muscles. Your therapist will provide feedback and teach you how to connect to the areas of tension.

If you, a friend or family member is struggling with OASIS and/or painful intercourse, please seek out medical advice. Let’s keep the conversation going and encourage women to seek out the help they need to get back to the life they want.


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