Risk factors for the recurrence of obstetrical anal sphincter injury and the role of a mediolateral episiotomy: an analysis of a national registry

Occurrence and risk factors for second-degree perineal tears: A prospective cohort study using a detailed classification system

BACKGROUND

The amount of tissue trauma within second-degree perineal tears varies widely. Therefore, subcategorization of second-degree tears and a better understanding of their occurrence and risk factors are needed. The aim of this study was to assess the occurrence of perineal tears when second-degree tears were subcategorized. Furthermore, we aimed to assess the association between variables related to perineal anatomy and other potential risk factors, with second-degree tear subcategories.

METHODS

This prospective cohort study included 880 primiparous and multiparous women giving birth to one child vaginally. Perineal tears were categorized using the classification system recommended by the Royal College of Obstetricians and Gynaecologists. In addition, second-degree tears were subcategorized as 2A, 2B, or 2C according to the percentage of damage to the perineal body. Selected variables related to perineal anatomy were as follows: length of genital hiatus; perineal body length; and previous perineal trauma. Risk factors for second-degree tear subcategories were analyzed using a multinominal regression model.

RESULTS

Perineal tears occurred as follows: first-degree: 35.6% (n = 313), 2A: 16.3% (n = 143), 2B: 9.1% (n = 80), 2C: 6.6% (n = 58), and third- or fourth-degree: 1.6% (n = 14). In total, 169/880 participants underwent an episiotomy. When episiotomies were excluded, the risk for 2B, or 2C tears increased with smaller genital hiatus, larger perineal body, previous perineal trauma, primiparity, higher gestational age, instrumental vaginal delivery and fetal presentation other than occiput anterior.

CONCLUSION

The occurrence of second-degree tear subcategories was 16.3% for 2A tears, 9.1% for 2B tears, and 6.6% for 2C tears. Factors related to perineal anatomy increased the odds for experiencing a second-degree tear in a more severe subcategory.

Risk indicators for obstetrical anal sphincter injury in vaginal birth after caesarean section compared to first vaginal delivery

OBJECTIVES

Comparison of the rate of obstetric anal sphincter injury (OASI) between women having their first vaginal birth after caesarean section (CS) and true nulliparous women with a vaginal delivery. Assessment of risk indicators for OASI in women with vaginal birth after one CS (VBAC).

STUDY DESIGN

28 535 women with their first VBAC and a cohort of 275 439 nulliparous women with a vaginal delivery of a liveborn infant in a cephalic position from the Dutch perinatal registry were analyzed. We compared the OASI rate with univariate and multivariate analysis. In women with VBAC possible risk indicators for OASI were assessed using univariate and multivariate logistic regression analysis.

RESULTS

The rate of OASI was 5.2% in women with vaginal birth after CS and 4.0% in women with a first vaginal delivery. The adjusted OR (aOR) for vaginal birth after an elective CS was higher (aOR 1.34, 95% CI 1.23-1.47) compared to vaginal birth after an emergency CS (aOR 1.16, 95% CI 1.08-1.25). In women with vaginal birth after emergency CS, the aOR for the indication non-progressive labor was 1.18 (95% CI 1.08-1.29), whereas CS for suspected fetal distress was not significantly associated with obstetric anal sphincter injury in VBAC. In the 28 535 women with a VBAC, mediolateral episiotomy (MLE), birth weight < 3000 g and maternal age < 25 years were associated with a significantly lower rate of OASI. A gestational age of 42 weeks, birth weight ≥ 3500 g, operative vaginal delivery and duration of the 2nd stage of labour of ≥ 60 min were associated with a significantly higher rate of OASI.

CONCLUSIONS

Women with a VBAC have a higher rate of OASI in comparison with women with a first vaginal delivery, with the exception of women with a vaginal birth after an emergency CS for suspected fetal distress. Factors associated with a significantly lower rate for OASI were MLE, maternal age < 25 and birth weight < 3000 g. A gestational age of 42 weeks, birth weight between 3500 and 4000 g and ≥ 4000 g, operative vaginal delivery and duration of the 2nd stage of delivery longer dan 60 min were associated with a significantly higher rate of OASI.

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.

European guidelines on perinatal care- Peripartum care Episiotomy

OF RECOMMENDATIONS1. Episiotomy should be performed by indication only, and not routinely (Moderate quality evidence +++-; Strong recommendation). Accepted indications for episiotomy are to shorten the second stage of labor when there is suspected fetal hypoxia (Low quality evidence ++-; Weak recommendation); to prevent obstetric anal sphincter injury in vaginal operative deliveries, or when obstetric sphincter injury occurred in previous deliveries (Moderate quality evidence +++-; Strong recommendation)2. Mediolateral or lateral episiotomy technique should be used (Moderate quality evidence +++-; Strong recommendation). Labor ward staff should be offered regular training in correct episiotomy techniques (Moderate quality evidence +++-; Strong recommendation).3. Pain relief needs to be considered before episiotomy is performed, and epidural analgesia may be insufficient. The perineal skin needs to be tested for pain before an episiotomy is performed, even when an epidural is in place. Local anesthetics or pudendal block need to be considered as isolated or additional pain relief methods (Low quality evidence ++-; Strong recommendation).4. After childbirth the perineum should be carefully inspected, and the anal sphincter palpated to identify possible injury (Moderate quality evidence +++-; Strong recommendation). Primary suturing immediately after childbirth should be offered and a continuous suturing technique should be used when repairing an uncomplicated episiotomy (High quality evidence ++++; Strong recommendation).

Recognition and Management of Pelvic Floor Disorders in Pregnancy and the Postpartum Period

Often considered a condition of aging women, pelvic floor disorders may initially present in pregnancy and postpartum, having a negative impact on quality of life during this important time in a woman's life. This review outlines the clinical approach to implementing pelvic health into obstetric care through education and promotion of pelvic health in pregnancy, screening for pelvic floor disorders routinely, and providing support through resources, treatment, and referrals if pelvic floor disorders develop during pregnancy and postpartum.