Risk of recurrence and subsequent delivery after obstetric anal sphincter injuries

Abstract

Objective To investigate the recurrence risk, the likelihood of having further deliveries and mode of delivery after third to fourth degree obstetric anal sphincter injuries (OASIS).Design Population-based cohort study.Setting The Medical Birth Registry of Norway.Population A cohort of 828 864 mothers with singleton, vertexpresenting infants, weighing 500 g or more, during the period 1967-2004.Methods Comparison of women with and without a history of OASIS with respect to the occurrence of OASIS, subsequent delivery rate and planned caesarean rate.Main outcome measures OASIS in second and third deliveries, subsequent delivery rate and mode of delivery.Results Adjusted odds ratios of the recurrence of OASIS in women with a history of OASIS in the first, and in both the first and second deliveries, were 4.2 (95% CI 3.9-4.5; 5.6%) and 10.6 (95% CI 6.2-18.1; 9.5%), respectively, relative to women without a history of OASIS. Instrumental deliveries, in particular forceps deliveries, birthweights of 3500 g or more and large maternity units were associated with a recurrence of OASIS. Instrumental delivery did not further increase the excess recurrence risk associated with high birthweight. A man who fathered a child whose delivery was complicated by OASIS was more likely to father another child whose delivery was complicated by OASIS in another woman who gave birth in the same maternity unit (adjusted OR 2.1; 95% CI 1.2-3.7; 5.6%). However, if the deliveries took place in different maternity units, the recurrence risk was not significantly increased (OR 1.3; 95% CI 0.8-2.1; 4.4%). The subsequent delivery rate was not different in women with and without previous OASIS, whereas women with a previous OASIS were more often scheduled to caesarean delivery.Conclusion Recurrence risks in second and third deliveries were high. A history of OASIS had little or no impact on the rates of subsequent deliveries. Women with previous OASIS were delivered more frequently by planned caesarean delivery.

Risk of recurrence, subsequent mode of birth and morbidity for women who experienced severe perineal trauma in a first birth in New South Wales between 2000 –2008: a population based data linkage study

“…For women who are symptomatic for urinary, flatus or faecal incontinence, or have findings that deviate from normal via manometric or endoanal ultrasonography associated with severe perineal trauma, it is suggested that an elective caesarean section should be recommended by the health care professional [3]. However, debate continues as to the most appropriate management of the subsequent mode of birth following severe perineal trauma, with discussions focussed around the protective mechanisms, potential morbidities and increased risk of subsequent perineal trauma associated with operative vaginal and vaginal births [3,18,20,21,26]. …”

“…Some women who experience severe perineal trauma express a preference for a vaginal birth subsequently, despite their fears regarding risk of recurrence [16]. There are contradictory findings reported in the literature regarding the risk of recurrence for women who have experienced third or fourth degree perineal trauma [18-21]. A review conducted by Edwards et al (2006) reviewed 271 cases, from 1991 to 2003, of women who experienced a subsequent labour and birth following severe perineal trauma with the first birth.…”

“…A cohort study conducted by Baghestan et al (2011) reported that an obstetric history of severe perineal trauma in the first or second birth increased the likelihood of repeat trauma occurring in the third birth. Likewise women who experienced severe perineal trauma were less likely to have a second pregnancy compared with women who had no history of severe perineal trauma (66.7% versus 76.9%); however these findings were not tatistically significant [18]. The risk is reported to increase in large maternity units (>3000 births per annum), when the newborn weight is above 3500 grams, and when forceps are used during the second stage of labour [18,19,21].…”

Women’s experiences following severe perineal trauma: a qualitative study

“…Severe perineal trauma (SPT) is defined as a third degree tear, which involves injury to the perineum which extends to the anal sphincter complex; or a fourth degree tear, which involves injury to the perineum involving the external, internal and epithelium of the anal sphincter [3]. It is reported that internationally the incidence of SPT ranges from 05-10% [4,5]. While some women may experience no symptoms, other women may experience any or all symptoms including dyspareunia, stress or urge urinary incontinence, flatus and/or faecal incontinence, and are at risk of developing co-morbidities including pelvic organ prolapse and vesicovaginal fistulas [6-8].…”

The long-term physical, emotional and psychosexual outcomes related to anal incontinence after severe perineal trauma at childbirth

“…In women who suffered OASIS at first birth, the incidence of a repeat OASIS has been shown to be 8.4% in hospital-based studies 2 and 7.2% in population-based studies 3 in the United Kingdom. In other countries, the rate of repeat OASIS in hospital-based and population-based studies has been reported to range widely from 2.0 to 7.2% 4,5 and from 5.6 to 7.1% 6,7 , respectively. Even though there are well defined risk factors for the occurrence of OASIS, such as nulliparity and instrument assistance at birth, the combination of these risk factors in different scoring systems does not allow the accurate prediction of OASIS 8 .…”