Authors (including presenting author) :
WAN YK(1)(2), KWOK PK(1)(2), CHEUNG RYK(1)(2), CHAN SSC(1)(2)
Affiliation :
(1)Department of Obstetrics and Gynaecology, Prince of Wales Hospital,(2) Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong
Introduction :
Obstetrics anal sphincter injury (OASIS) is the leading cause of anal incontinence in women. If OASIS was found immediately after delivery, proper repair can be done to reduce the risk of long term complications. The reported rate of OASIS in Hong Kong was much lower than the international figures. It raised the possibility of occult OASIS, which refers to the injury that was not detected immediately after delivery, thus missed. Potential long term complications may be anticipated. Besides, proper assessment and counselling for future mode of delivery was not possible for this group of women.
Objectives :
To study the true prevalence of OASIS in Hong Kong
Methodology :
This study recruited a cohort of women at 6-12 months after their first vaginal delivery. Written consent was obtained. Details of the delivery and any perineal tear, assessed by midwife or doctor after delivery, were collected from medical records. Symptoms of anal incontinence were assessed by validated questionnaire, namely Pelvic Floor Distress Inventory. Postnatal endoanal ultrasound was performed to evaluate internal and external anal sphincters with offline analysis to look for any injury.
Result & Outcome :
Total 542 women were studied, including 205 having normal vaginal delivery (NVD) and 337 having instrumental delivery (ID) from August 2009 to Dec 2014. All of them had no anal incontinence before delivery. Only 6 (1.1%) were OASIS detected immediately after delivery and repair was done by experienced obstetricians. The prevalence of OASIS detected by endoanal ultrasound was 7.8% (n=16) (95% CI 4.1-11.5%) and 5.6% (n=19) (95% CI 3.1-8.1%) in NSD and ID group, respectively. The occult OASIS rate was 7.8% (95% CI 4.1%, 11.5%) and 3.8% (95% CI 1.8-5.8%) in NSD and ID group, respectively. Overall, 82.9% of OASIS detected by endoanal US were missed clinically. Birth weight was significantly higher in the OASIS group (P=0.012). By 6-12 months after delivery, 5.5% (n=30) and 17.9% (n=97) of women reported fecal and flatal incontinence, respectively, among which 3 suffered from occult injury. There is a need to enhance the training of midwives and doctors in postpartum perineal assessment in order to reduce occult OASIS rate. A dedicated perineal clinic should be established to assess women who suffer from OASIS and symptoms of anal incontinence postnatally and antenatally for counselling on mode of delivery in their subsequent pregnancies to improve our care.
Co-location with:
