Dr. Jena Hall, Jessica Pudwell, Dr. Marie-Andrée Harvey
Dept OBGYN, Queen’s University, Kingston Health Sciences Centre, Kingston, ON, Canada
BACKGROUND: Obstetrical anal sphincter injuries (OASIS) occur in 4-6.6% of vaginal deliveries. They are associated with both short and long-term maternal morbidity, including defecation problems in the immediate postpartum period and long-term anal incontinence. Some studies have examined whether subsequent pregnancy, and mode of delivery, following OASIS affect anal incontinence symptoms, however the evidence is mixed, making it difficult for obstetrical providers to counsel their patients.
OBJECTIVES: The current study aimed to compare symptoms in those women with a history of OASIS who had subsequent vaginal deliveries to those with OASIS who did not have further vaginal deliveries, as well as to those women without OASIS, who either remained primiparous or went on to have subsequent vaginal deliveries.
METHODS: Ethics approval (OBGY-245-13) was obtained from the Queen’s University and Affiliated Teaching Hospitals Health Sciences Research Ethics Board. Mail-out surveys which included demographics, Wexner score, CRADI8, Manchester General Health and Incontinence Impact Score, were sent to 247 women who suffered an OASIS at their first delivery between 2007-2012. Since the rate of anal incontinence in women who do not suffer OASIS is not well studied, for comparison, we sent the same questionnaires to 259 women who had vaginal deliveries during the same time frame, but who did not suffer OASIS. Exclusion criteria included multiple gestation, gross anatomic fetal anomalies, IUFD, GA < 37 weeks, and maternal age < 15 years at the time of delivery. To compare outcomes, t-test, Mann-Whitney-U and chi squared analyses were used. Logistic regression models were used to adjust for number of vaginal deliveries. Statistical analysis was completed using IBM SPSS statistics v27.
RESULTS: Survey response rate for OASIS and control groups were 36.8% (91/247) and 23.2% (60/259) respectively. During an in-depth chart review of those who returned surveys, we identified that hospital diagnostic codes did not consistently match hospital records. For this reason, 5 OASIS and 14 controls were excluded, and 5 controls were moved to the OASIS group. Within the OASIS cohort, 80 (88%) had a 3rd degree tear and 9 (10%) had a 4th degree tear. Women with OASIS had a longer mean (SD) active second stage (110 (61) vs 77 (57) minutes, p=0.01), a higher mean (SD) infant birth weight (3725g (446) vs 3499g (420), p=0.01), and were more likely to have had an operative vaginal delivery (57% vs 25%) (p=0.02).
Women with OASIS were more likely to experience flatal incontinence (44% vs 18%) (aOR=3.74, 95% CI 1.41, 9.94; p=0.008), but there was no difference in frequency of fecal incontinence (11% vs 6%) (aOR=1.96, 95% CI 0.41, 9.64; p=0.41). There was a significant difference in symptom severity between the two groups, with significantly more women in the OASIS cohort above the median Manchester questionnaire score (aOR=3.16, 95% CI 1.24, 8.05; p=0.016). There was no statistical difference in the perception of impact of symptoms on quality of life. When adjusted for number of subsequent vaginal deliveries, these results remained true.
CONCLUSION: Within this study population, although women with a history of OASIS have more frequent flatal incontinence and more severe symptoms than those without a history of OASIS, this difference it does not translate to impact upon quality of life metrics.