Postpartum anal incontinence in women with and without obstetric anal sphincter injuries

Anal incontinence following obstetric anal sphincter injury: Is there a difference between subtypes? A systematic review

AIMS

Obstetric anal sphincter injury (OASI) is associated with long-term anal incontinence (AI). We aimed to address the following questions: (a) are women with major OASI (grade 3c and 4) at higher risk of developing AI when compared to women with minor OASI (grade 3a and 3b)? (b) is a fourth-degree tear more likely to cause AI over a third-degree tear?

METHODS

A systematic literature search from inception until September 2022. We considered prospective and retrospective cohort studies, cross-sectional and case-control studies without language restrictions. The quality was assessed by the Newcastle-Ottawa Scale and the Joanna Briggs Institute critical appraisal checklist. Risk ratios (RRs) were calculated to measure the effect of different grades of OASI.

RESULTS

Out of 22 studies, 8 were prospective cohort, 8 were retrospective cohort, and 6 were cross-sectional studies. Length of follow-up ranged from 1 month to 23 years, with the majority of the reports (n = 16) analysing data within 12-months postpartum. Third-degree tears evaluated were 6454 versus 764 fourth-degree tears. The risk of bias was low in 3, medium in 14 and high in 5 studies, respectively. Prospective studies showed that major tears are associated with a twofold risk of AI for major tears versus minor tears, while retrospective studies consistently showed a risk of fecal incontinence (FI) which was two- to fourfold higher. Prospective studies showed a trend toward worsening AI symptoms for fourth-degree tears, but this failed to reach statistical significance. Cross-sectional studies with long-term (≥5 years) follow-up showed that women with fourth-degree tear were more likely to develop AI, with an RR ranging from 1.4 to 2.2. Out of 3, 2 retrospective studies showed similar findings, but the follow-up was significantly shorter (≤1 year). Contrasting results were noted for FI rates, as only 5 out of 10 studies supported an association between fourth-degree tear and FI.

CONCLUSIONS

Most studies investigate bowel symptoms within few months from delivery. Data heterogeneity hindered a meaningful synthesis. Prospective cohort studies with adequate power and long-term follow-up should be performed to evaluate the risk of AI for each OASI subtype.

The incidence of anal incontinence following obstetric anal sphincter injury graded using the Sultan classification: a network meta-analysis

OBJECTIVE

This study aimed to systematically determine and compare the incidence of anal incontinence between those with different grades of obstetric anal sphincter injury.

DATA SOURCES

Ovid MEDLINE, Embase, and the Cochrane Library were searched from January 2000 to April 2021.

STUDY ELIGIBILITY CRITERIA

Observational studies investigating the incidence of anal incontinence following an obstetric anal sphincter injury that was graded using the Sultan classification were eligible for inclusion. To allow comparison between individual tear grades (3a, 3b, 3c, fourth), a network meta-analysis was performed using Stata (version 15.1).

METHODS

For binary outcomes, odds ratios with corresponding 95% confidence intervals were reported. Obstetric anal sphincter injury grades were ranked from the best clinical outcome to the worst clinical outcome. The percentage chance of each grade taking each rank with regards to outcome was calculated. Study quality and risk of bias was assessed using the relevant tool from the Joanna Briggs Institute.

RESULTS

Of the 696 studies identified, 10 were eligible for inclusion and were included in the network meta-analysis (n=2467 women). The mean incidence of anal incontinence among those with 3a tears was 22.4% (range, 6.1%-51.2%), 24.9% (range, 6.9%-46.7%) among those with 3b tears, 26.8% (range, 0%-55.6%) among those with 3c tears, and 28.6% (0%-71.4%) among those with fourth-degree tears. Anal incontinence incidence was found to be significantly higher among those with 3c (odds ratio, 1.79; 95% confidence interval, 1.09-2.94) and fourth-degree tears (odds ratio, 2.37; 95% confidence interval, 1.40-4.02) than among those with 3a tears. In addition, anal incontinence incidence was significantly higher among those with fourth-degree tears (odds ratio, 1.89; 95% confidence interval, 1.10-3.22) than among those with 3b tears. Those with 3a tears had the highest probability of having the best clinical outcome; those with 3b; second-, 3c; third- and fourth-degree tears had the highest probability of having the worst clinical outcome. Overall, all studies had a high or unclear risk of bias across 1 or more assessed element.

CONCLUSION

This was a network meta-analysis comparing the incidence of anal incontinence among those with different grades of obstetric anal sphincter injury. Increasing tear-grade severity is associated with worse clinical outcomes. This study provides useful, clinically applicable information that can assist clinicians in the counseling of women following an obstetric anal sphincter injury. In addition, it highlights the importance of accurately diagnosing the obstetric anal sphincter injury grade and subsequently performing the appropriate repair.

[Postpartum fecal incontinence. State of the problem]

A review of the current national and foreign literature is devoted to epidemiology, risk factors, causes, diagnosis and modern treatment approaches for fecal incontinence (FI). Incidence of FI in early and delayed period after childbirth is 30% or more. At the same time, up to 87% of postpartum injuries of anal sphincter remain undiagnosed. Importantly, routine caesarean section does not reduce the risk of incontinence. In addition to typical complaints of spontaneous gas and stool, diagnosis of FI after childbirth includes transrectal ultrasound, MRI, anorectal manometry and pudendal nerve terminal motor latency testing. Survey of proctologists from different regions of Russia revealed a high demand from medical community for educational programs devoted to diagnosis, treatment and rehabilitation of patients with postpartum perineal injuries.

Obstetrical anal sphincter injury and unnecessary episiotomy are both associated with anal incontinence 8 years after childbirth: A nationwide database analysis

OBJECTIVE

to assess the relationship between anal incontinence (AI) 8 years after childbirth and the occurrence of Obstetrical Anal Sphincter Injury (OASI) and/or performance of an episiotomy during childbirth.

METHODS

This is a nationwide database analysis performed on two national medico-administrative databases, including all the women aged ≥18 years who delivered infants in France in 2012. The main outcome measure was AI in the 8-years after delivery.

RESULTS

Of the 163,443 perineal tears reported, 0.47% were grade-3 and 0.08% were grade-4; 8,938 women experienced AI (1.33%) and 261 women experienced severe AI (0.04%). Episiotomies performed in the absence of risk factors for OASI were significantly associated with an increased risk of AI (Odds Ratio (OR)=1.59; 95% Confidence Interval (CI):1.49-1.69;p<0.001). Grade 3 and 4 OASI also significantly increased the risk of AI and severe AI. Mediolateral episiotomy was preventative of OASI when performed in subjects at risk (OR=0.26; 95% CI:0.23-0.30; p<0.001) but contributed to OASI in the absence of risk (OR=2.18; 95% CI:1.98-2.40; p<0.001).

CONCLUSIONS

OASI is a risk factor for AI. Episiotomies could reduce the occurrence of OASI, but they could also have a increase the risk of long-term AI in the absence of risk factors for OASI.

Association between birth weight and head circumference and obstetric anal sphincter injury severity

OBJECTIVE

To identify risk factors for increasing severity of OASI and evaluate its possible correlation with two known risk factors-birth weight (BW) and neonatal head circumference (HC).

METHODS

We performed a retrospective cohort study at a university affiliated hospital between 2003 and 2019. We compared five groups of patients - according to presence and degree of perineal laceration - 3a, 3b, 3c and 4 and patients without OASI. Additionally, four parameters were defined to assess their relation to the severity of OASI: (1) BW ≥ 90th and HC < 90th percentiles; (2) BW < 90th and HC ≥ 90th percentile; (3) BW and HC ≥ 90th percentile and (4) BW and HC < 90th percentiles.

RESULTS

During the study period, 150,221 deliveries were evaluated. Parturients were allocated according to OASI severity - 455 patients had a 3rd (3a, 3b or 3c) or 4th degree perineal tear, while 110,966 patients had no OASI. Allocation to subgroups according to offspring anthropomorphic measures showed that as fetal size parameters increased, the rate of more severe tears increased, particularly in women delivering neonates with HC ≥ 90th percentile. Multinomial regression analysis was performed for each 3rd degree OASI subgroup. This analysis demonstrated the odds for OASI gradually increase with tear severity for BW ≥ 90th percentile and the combined BW and HC ≥ 90th percentile parameters, as compared with neonates with HC and BW < 90th percentile.

CONCLUSIONS

Birth weight and head circumference above the 90th percentile are correlated with increased degree of OASI severity.