Umeå universitets logga

Background: Obstetric anal sphincter injuries (OASIS) after vaginal delivery are the most common cause of anal incontinence in women. Symptoms range from faecal urgency and soiling to inability to control flatus and passive faecal incontinence. OASIS are also associated with urinary incontinence, perineal pain, and sexual dysfunction. Apart from being a challenge to diagnose and treat, these conditions often result in social stigma and embarrassment, and in many cases have a great impact on emotional and physical health.

Caesarean section has developed over several hundred years, from a procedure with 100 % mortality for both mother and child, to routine surgery that is rapidly increasing in many countries. However, both caesarean section and vaginal delivery are associated with complications that can affect the woman for the rest of her life. The aim of this thesis was primarily to investigate surgical complications after delivery.

Methods: Papers I-III were population-based cohort-studies utilising national registries to examine the risk for anal incontinence, cardiovascular complications, and other surgical complications such as bowel obstruction, incisional hernia, and abdominal pain. Paper IV was a diagnostic cohort study comparing the traditional clinical method using inspection and palpation, to a new method with three-dimensional endoanal ultrasound (3D-EAUS) to diagnose anal sphincter injuries after delivery.

Results: The risk for being diagnosed with anal incontinence after vaginal delivery was almost twice that after caesarean section. On the other hand, caesarean section was associated with a greater risk for serious cardiovascular complications, bowel obstruction, and incisional hernia. High maternal age, overweight and smoking were all risk factors for complications. Instrumental delivery, in particular, increased the risk for anal incontinence. In Study IV, more sphincter injuries were diagnosed using the 3D-EAUS than by clinical examination. However, some injuries diagnosed clinically could not be identified with 3D-EAUS.

Conclusions: Both vaginal and caesarean delivery are associated with certain risks. Although the increased risk for cardiovascular complications, bowel obstruction, and incisional hernia must be taken into consideration, there seem to be a gain in reducing the risk for anal incontinence, when performing a caesarean section on the right indication. 3D-EAUS assessment of the anal sphincters after delivery is a new technique that with further improvement could be an important tool in the prevention of anal incontinence.