Obstetric pelvic floor and anal sphincter injuries

Effect of a subsequent pregnancy on anal sphincter integrity and function after obstetric anal sphincter injury (OASI)

Introduction and hypothesis

Endoanal ultrasound (EAUS) and anal manometry are used in the assessment women with a history of obstetric anal sphincter injury (OASI), both postpartum and in a subsequent pregnancy, to aid counselling regarding mode of delivery (MOD).

Methods

A prospective observational study between 2012 to 2020 was completed. Women were reviewed 3 months postpartum following OASI and in the second half of a subsequent pregnancy. Anorectal symptoms were measured using the validated St Mark’s Incontinence Score (SMIS: asymptomatic to mild symptoms = ≤ 4). Anal manometry (incremental maximum squeeze pressure [iMSP: normal = > 20 mmHg]) and EAUS (abnormal = sphincter defect > 1 h in size) were performed.

Results

One hundred forty-six women were identified and 67.8% had an anal sphincter defect ≤ 1 h in size postnatally. In those with a defect ≤ 1 h, postpartum mean iMSP and SMIS significantly improved in a subsequent pregnancy (p = 0.04 and p = 0.01, respectively). In women with a defect > 1 h, there was no significant difference between the mean iMSP or SMIS score postnatally compared to a subsequent pregnancy. At both time points, significantly more women had an anal sphincter defect ≤ 1 h and SMIS of ≤ 4 (p = 0.001 and p < 0.001 respectively) compared to those with a defect < 1 h. In addition, significantly more women had an anal sphincter defect ≤ 1 h and iMSP ≥ 20 mmHg (p < 0.001). Overall, out of the 146 women included in this study, 76 (52.1%) with a defect ≤ 1 h also had an iMSP ≥ 20 mmHg and SMIS ≤ 4 at 3 months postpartum.

Conclusions

Women who remain asymptomatic with normal anal manometry and no abnormal sphincter defects on EAUS postnatally do not need to have these investigations repeated in a subsequent pregnancy and can be recommended to have a vaginal delivery. If our protocol was modified, over half of the women in this study could have had their MOD recommendation made in the postnatal period alone.

Women's experience of obstetric anal sphincter injury following childbirth: An integrated review

BACKGROUND

Perineal injury during childbirth is a very common event which affect women during childbirth. Significant morbidities are associated with third-and-fourth degree perineal tears in particular, also referred to as obstetric anal sphincter injuries (OASIS). With an increasing global birth rate and rising interventions in birth, the incidence of perineal trauma following vaginal birth is increasing on an international scale, impacted also by more accurate classification and definitions of OASIS and increased pre-existing co morbidities amongst affected women. The consequences of OASIS can be physically and psychologically distressing for affected women and have significant impact on quality of life.

METHODOLOGY

The aim of this integrative review was to examine women's experience of OASIS following childbirth using a systematic approach. This is presented in a five-stage process that includes problem identification, literature search, data extraction and evaluation, data analysis and presentation of results. A number of academic electronic databases were systematically searched and results are presented and analysed. Results of the complete search are presented in PRISMA format. Eight papers, which were assessed for quality using an appropriate appraisal tool, are included in the review and thematic analysis used to identify themes.

FINDINGS

The themes identified were; psychological consequences, the role of the health care professionals and implications for future pregnancies. Psychological consequences included anxiety, loneliness, isolation, shame, fear, many of which were associated with physical ramifications of OASIS and how these feelings affect activities of daily living. The importance of access to and support from health care professionals was highlighted. The impact the experience of OASIS had on women's decisions about future pregnancies was also evident.

CONCLUSION

The association between OASIS and maternal quality of life following childbirth can be substantial as evidenced by this literature review. The review identifies the need for improvement in the care and management of these women to alleviate the physical and psychological consequences of OASIS, including decisions in relation to future pregnancies and childbirth. Health care professionals caring for women in pregnancy and childbirth need to be educated and informed on the sequelae of OASIS, to ensure appropriate information and support is provided to these women and their families. Such knowledge may enable health care professionals to alleviate symptoms associated with OASIS and help women make sense and cope with their experiences.

A Quality Improvement Project Utilizing a Clinical Practice Guideline in Women During Second-Stage Labor

Second-stage labor is the most challenging stage of labor, as it requires increasing exertion of the birthing woman. Variances in nursing interventions in second-stage labor have an influence on outcomes. There is disparity in nursing care during second-stage labor. The purpose of this project was to evaluate a clinical practice guideline in second-stage labor with respect to positioning, timing of pushing, type of pushing effort, and the effect on birth method and perineal trauma. Spontaneous vaginal birth increased, vacuum extraction birth decreased, and vaginal birth after cesarean doubled. The rate of episiotomy decreased, the rate of multiple types of lacerations decreased, the rate of vaginal wall tears decreased, and the need for wound suturing of birth acquired lacerations decreased.

The impact of first birth obstetric anal sphincter injury on the subsequent birth: a population-based linkage study

BACKGROUND

With rising obstetric anal sphincter injury (OASI) rates, the number of women at risk of OASI recurrence is in turn increasing. Decisions regarding mode of subsequent birth following an OASI are complex, and depend on a variety of factors. We sought to identify the risk factors for OASI recurrence from first and subsequent births, and to investigate the effect of OASI birth factors on planned caesarean for the second birth.

METHODS

Using two linked population datasets from New South Wales, Australia, we selected women giving birth between 2001 and 2011 with a first birth OASI and a subsequent birth. Multivariable logistic regression was used to identify the association of first and second birth factors with OASI recurrence, and to determine which factors were associated with a planned pre-labour caesarean at the second birth.

RESULTS

Of 6,380 women with a first birth OASI who proceeded to a subsequent birth, 75.4% had a vaginal second birth, 19.4% a pre-labour caesarean, and 5.2% an intrapartum caesarean. Although the OASI recurrence rate of 5.7% was significantly higher than the first birth OASI rate of 4.5% (p < 0.01), this may not reflect a clinically significant increase. Following adjustment for first and second birth factors, first birth diabetes and second birthweight ≥3.5 kg were associated with increased likelihood of OASI recurrence, while first birthweight ≥4.0 kg and second gestation at 37-38 weeks were associated with decreased likelihood. A fourth degree tear at the first birth was the strongest factor associated with planned caesarean at the second birth, with other factors including epidural, spinal or general anaesthetic, birthweight, gestation, country of birth and maternal age.

CONCLUSIONS

Compared with previous reports, the low OASI recurrence rate (approximately one in twenty) may reflect appropriate decision-making about subsequent mode of delivery following first birth OASI. This assertion is supported by evidence of different risk profiles for women who have planned caesareans compared with planned vaginal births.