Third degree obstetric perineal tears: risk factors and the preventive role of mediolateral episiotomy

Objective To determine risk factors for third degree obstetric perineal tears and to give recommendations for prevention.
Design Retrospective case–control study.
Setting A teaching hospital in The Netherlands.
Participants and methods One hundred and twenty cases of vaginal delivery complicated by third degree perineal tear and 702 uncomplicated vaginal deliveries were compared, with respect to possible risk factors.
Results In a multivariate model high birthweight, forceps delivery, induced labour, epidural anaesthesia and parity were risk factors for anal sphincter tear. In addition, mediolateral episiotomy was associated with fewer sphincter injuries. Separate analysis of nulli- and multiparous women demonstrated that high birthweight and epidural anaesthesia (increased risk) and mediolateral episiotomy (decreased risk) were factors associated with anal sphincter tear only in nulliparous women.
Conclusions We found several risk factors for anal sphincter tear. Nulliparous women are at higher risk than multiparous women. Mediolateral episiotomy may be sphincter-saving especially in nulliparous women and therefore prevent them from chronic faecal incontinence.     

Factors predicting severe perineal trauma during childbirth: role of forceps delivery routinely combined with mediolateral episiotomy

OBJECTIVE: Anal sphincter injury and its sequelae are a recognized complication of vaginal childbirth. The aim of the present study was to identify risk factors for third- and fourth-degree perineal tears in patients undergoing either spontaneous or vaginal-assisted delivery by forceps routinely combined with mediolateral episiotomy. STUDY DESIGN: We retrospectively reviewed 5377 vaginal deliveries based on the analysis of the obstetric database and patient records of our department during a 5-year period from 1999 to 2003. Cases and control subjects were chosen randomly and patients' records were reviewed for the following variables: maternal age, parity, gestational age, tobacco use, gestational diabetes or pregnancy-induced hypertension, use of peridural anesthesia, duration of first and second stages of labor, use of mediolateral episiotomy, forceps combined with mediolateral episiotomy, induction of labor, infant head diameter, shoulder circumference, and birth weight. RESULTS: Of 5044 spontaneous vaginal deliveries 32 (0.6%) and of 333 assisted vaginal deliveries 14 (4.2%) patients sustained a perineal defect involving the external sphincter. An univariate analysis of these 46 cases and 155 randomly selected control subjects showed that low parity (P = .003; Mann-Whitney U test), prolonged first and second stages of labor (P = .001, P = .001), high birth weight (P = .031), episiotomy (P = .004; Fisher exact test), and forceps delivery (P = .002) increased the risk for sphincter damage. In multivariate regression models, only high birth weight (P = .004; odds ratio [OR] 1.68, 1.18-2.41, 95% confidence interval [CI]), and forceps delivery combined with mediolateral episiotomies (P < .001; OR 5.62, 2.16-14.62, 95% CI) proved to be independent risk factors. There was a statistical significant interaction of birth weight and head circumference (P = .012; OR 0.99, 0.98-0.99, 95% CI). Although the use of episiotomy conferred an increased risk toward a higher likelihood of severe perineal trauma, it did not reach statistical significance (P = .06; OR 2.15, 0.97-4.76, 95% CI). CONCLUSIONS: In consistence with previous reports, women who are vaginally delivered of a large infant are at a high risk for sphincter damage. Although the rate of these complications was surprisingly low in vaginally assisted childbirth, the use of forceps, even if routinely combined with mediolateral episiotomy, should be minimized whenever possible.     

Risk factors for third degree perineal ruptures during delivery

Objective To determine risk factors for the occurrence of third degree perineal tears during vaginal delivery.
Design A population-based observational study.
Population All 284,783 vaginal deliveries in 1994 and 1995 recorded in the Dutch National Obstetric Database were included in the study.
Methods Third degree perineal rupture was defined as any rupture involving the anal sphincter muscles. Logistic regression analysis was used to assess risk factors.
Main outcome measures An overall rate of third degree perineal ruptures of 1.94% was found. High fetal birthweight, long duration of the second stage of delivery and primiparity were associated with an elevated risk of anal sphincter damage. Mediolateral episiotomy appeared to protect strongly against damage to the anal sphincter complex during delivery (OR: 0.21, 95% CI: 0.20–0.23). All types of assisted vaginal delivery were associated with third degree perineal ruptures, with forceps delivery (OR: 3.33, 95%-CI: 2.97–3.74) carrying the largest risk of all assisted vaginal deliveries. Use of forceps combined with other types of assisted vaginal delivery appeared to increase the risk even further.
Conclusions Mediolateral episiotomy protects strongly against the occurrence of third degree perineal ruptures and may thus serve as a primary method of prevention of faecal incontinence. Forceps delivery is a stronger risk factor for third degree perineal tears than vacuum extraction. If the obstetric situation permits use of either instrument, the vacuum extractor should be the instrument of choice with respect to the prevention of faecal incontinence.     

Impact of Episiotomy During Operative Vaginal Delivery on Obstetrical Anal Sphincter Injuries

ObjectiveThe purpose of this study was to describe associations between episiotomy at the time of forceps or vacuum-assisted delivery and obstetrical anal sphincter injuries (OASIS).MethodsThis population-based retrospective cohort study used delivery information from a provincial perinatal clinical database. Full-term, singleton, in-hospital, operative vaginal deliveries of vertex-presenting infants from April 1, 2006 to March 31, 2016 were identified. Odds ratios (ORs) and 95% confidence intervals (CIs) for associations between episiotomy and third- or fourth-degree lacerations were calculated in multiple logistic regression models (Canadian Task Force Classification II-2).ResultsEpisiotomy was performed in 34% of 52 241 operative vaginal deliveries. OASIS occurred in 21% of forceps deliveries and 7.6% of vacuum deliveries. Episiotomy was associated with increased odds of severe perineal lacerations for vacuum deliveries among women with (OR 2.48; 95% CI 1.96–3.13) and without (OR 1.12; 95% CI 1.02–1.22) a prior vaginal delivery. Among forceps deliveries, episiotomy was associated with increased odds of OASIS for those with a previous vaginal delivery (OR 1.52; 95% CI 1.12–2.06), but it was protective for women with no previous vaginal delivery (OR 0.73; 95% CI 0.67–0.79). Midline compared with mediolateral episiotomy increased the odds of OASIS in forceps deliveries (OR 2.73; 95% CI 2.37–3.13) and vacuum deliveries (OR 1.94; 95% CI 1.65–2.28).ConclusionIn conclusion, results suggest that episiotomy should be used with caution, particularly among women with a previous vaginal delivery and in the setting of vacuum-assisted delivery. Episiotomy may protect against OASIS in forceps-assisted deliveries for women without a prior vaginal delivery.     

The impact of occiput posterior fetal head position on the risk of anal sphincter injury in forceps-assisted vaginal deliveries

OBJECTIVE: A forceps-assisted vaginal delivery is a well-recognized risk factor for anal sphincter injury. Some studies have shown that occiput posterior (OP) fetal head position is also associated with an increased risk for third- or fourth-degree lacerations. The objective of this study was to assess whether OP position confers an incrementally increased risk for anal sphincter injury above that present with forceps deliveries. STUDY DESIGN: This was a retrospective cohort study of 588 singleton, cephalic, forceps-assisted vaginal deliveries performed at our institution between January 1996 and October 2003. Maternal demographics, labor and delivery characteristics, and neonatal factors were examined. Statistical analysis consisted of univariate statistics, Student t test, chi2, and logistic regression. RESULTS: The prevalence of occiput anterior (OA) and OP positions was 88.4% and 11.6%, respectively. The groups were similar in age, marital status, body mass index, use of epidural, frequency of inductions, episiotomies, and shoulder dystocias. The OA group had a higher frequency of rotational forceps (16.2% vs 5.9%, P = .03), greater birth weights (3304 +/- 526 g vs 3092 +/- 777 g, P = .004), and a larger percentage of white women (48.8% vs 34.3%, P = .04). Overall, 35% of forceps deliveries resulted in a third- or fourth-degree laceration. Anal sphincter injury occurred significantly more often in the OP group compared with the OA group (51.5% vs 32.9%, P = .003), giving an odds ratio of 2.2 (CI: 1.3-3.6). In a logistic regression model that controlled for occiput posterior position, maternal body mass index, race, length of second stage, episiotomy, birth weight, and rotational forceps, OP head position was 3.1 (CI: 1.6-6.2) times more likely to be associated with anal sphincter injury than OA head position. CONCLUSION: Forceps-assisted vaginal deliveries have been associated with a greater risk for anal sphincter injury. Within this population of forceps deliveries, an OP position further increases the risk of third- or fourth-degree lacerations when compared with an OA position.     

Is severe perineal damage increased in women with prior anal sphincter injury?

OBJECTIVE: There is conflicting data in the literature regarding the risk of obstetric anal sphincter laceration in patients with a prior laceration. This retrospective chart review seeks to examine the risk of recurrence of obstetric anal sphincter lacerations. METHODS: Patients who sustained anal sphincter laceration at delivery during a 13-year time period from January 1991 to December 2003 were identified from the medical records database at Temple University Hospital. All subsequent deliveries in this group of patients were extracted from the database. Chart review was performed on all subsequent deliveries with specific attention to demographic factors such as age, race, parity, etc., maternal weight, fetal weight, presence of maternal diabetes, and labor characteristics such as induction or augmentation of labor, instrumentation at delivery (vacuum or forceps), use of episiotomy, and degree of perineal laceration. RESULTS: There were 23 451 vaginal deliveries at Temple University Hospital between January 1, 1991 and December 31, 2003. Anal sphincter laceration was noted in 778 subjects. Subsequent deliveries among the group of patients with prior sphincter tears numbered 271. Six (2.4%) patients had recurrence of anal sphincter lacerations, and five of them were third degree lacerations. The rate of recurrent lacerations was not significantly different from the rate of initial lacerations (2.4% vs. 3.3%; odds ratio 0.72, 95% confidence interval 0.33-1.59; p = 0.4). Women who sustained recurrent lacerations were older, more obese (mean weight 92 kg vs. 82 kg), had larger babies (3506 g vs. 3227 g), and were more likely to have episiotomies (66.7% vs. 7%) or instrumental deliveries (33.3 vs. 6.5%). CONCLUSION: Prior anal sphincter laceration does not result in an increased rate of recurrence. Operative vaginal delivery particularly with episiotomy is a risk factor for both initial and recurrent laceration.     

Risk Factors for Obstetric Anal Sphincter Injury: A Prospective Study

Abstract: Background: Anal incontinence is an embarrassing condition that is largely underreported. Obstetric anal sphincter injuries are the major etiological factor. Recognition of risk factors may minimize the development of sphincter injuries. The objective of this study was to identify risk factors for sphincter injuries and measure dimensions of mediolateral episiotomies. Methods: Women expecting their first vaginal delivery were invited to participate, and an experienced research fellow performed a perineal and rectal examination and classified tears according to the new international classification. Dimensions of episiotomies were measured and obstetric variables recorded prospectively. Results: Of the 241 women recruited, 59 (25%) sustained sphincter injuries. Univariate analysis revealed that forceps delivery OR 4.03 (1.63–9.92), vacuum extraction OR 2.64 (1.25–5.54), gestation > 40 weeks OR 3.18 (2.35–4.29), and mediolateral episiotomy OR 5.0 (2.64–9.44) were associated with these injuries. In addition, compared with women who had no injuries, sphincter injuries were more common with higher birthweight (3.51 vs 3.17 kg, p < 0.01), larger head circumference (34.3 vs 33.3 cm, p < 0.01), and longer second stage of labor (76 vs 51 min, p < 0.01). Multiple logistic regression revealed higher birthweight and mediolateral episiotomy OR 4.04 (1.71–9.56) as independent risk factors. Episiotomies angled closer to the midline were significantly associated with such injuries (26 vs 37 degrees, p = 0.01). No midwife and only 13 (22%) doctors performed truly mediolateral episiotomies. Conclusions: Mediolateral episiotomy is an independent risk factor for anal sphincter injuries. Although a liberal policy of mediolateral episiotomy does not appear to reduce the risk of such injuries, it may be related to inappropriate technique. A concerted approach to educate trainees in appropriate episiotomy technique and identification of sphincter injuries is imperative to enable reexamination of the true merits or disadvantages of mediolateral episiotomy. (BIRTH 33:2 June 2006)     

Risk factors associated with anal sphincter tear: a comparison of primiparous patients,vaginal births after cesarean deliveries,and patients with previous vaginal delivery

OBJECTIVE: This study was conducted to identify obstetric risk factors for anal sphincter tear in primiparous patients, patients with a previous cesarean delivery (VBAC), and patients with a previous vaginal delivery (PVD). STUDY DESIGN: An obstetrics automated record system was accessed to retrospectively review records of all singleton vaginal deliveries at greater than 36 weeks' gestation (excluding breech and stillbirth) from 1995 through 2000 (n = 10,928). A number of potential risk factors for anal sphincter tear (third- and fourth-degree episiotomy extensions and lacerations) were tested with use of multivariate logistic regression analysis. RESULTS: The risk of anal sphincter tear was significantly increased with primiparity (relative risk [RR] 4.08) and VBAC (RR 5.46) compared with PVD, birth weight greater than 4000 g (RR 2.41), forceps delivery (RR 6.00), vacuum delivery (RR 2.18), shoulder dystocia (RR 3.28), and episiotomy (RR 2.59). CONCLUSION: Efforts to prevent anal sphincter tear might include reconsideration of modifiable risk factors such as episiotomy, operative vaginal delivery, and VBAC.     

Risk factors for perineal injury during delivery

OBJECTIVE: We sought to identify risk factors for anal sphincter injury during vaginal delivery. STUDY DESIGN: This was a retrospective, case-control study. We reviewed 2078 records of vaginal deliveries within a 2-year period from May 1, 1999, through April 30, 2001. Cases (n = 91) during the study period were defined as parturients who had documentation of greater than a second-degree perineal injury. Control subjects (n = 176), who were identified with the use of a blinded protocol, included women who were delivered vaginally with less than or equal to a second-degree perineal injury. For each patient, we reviewed medical and obstetrics records for the following characteristics: maternal age, race, weight, gestational age, parity, tobacco use, duration of first and second stages of labor, use of oxytocin, use of forceps or vacuum, infant birth weight, epidural use, and episiotomy use. RESULTS: Of the 2078 deliveries that were reviewed, we discovered 91 cases (4.4%) of documented anal sphincter injury. The mean maternal age of our sample was 24.9 +/- 5.9 years). Nearly two thirds (63.2%) were white; 26.7% were black, and 10.1% were of other racial backgrounds. Forceps were used in 51.6% of deliveries that resulted in tears (cases), compared to 8.6% of deliveries without significant tears (control subjects, P <.05). Using cases and control subjects with complete data (cases, 82; control subjects, 144), delivery with forceps was associated with a 10-fold increased risk of perineal injury (odds ratio, 10.8; 95% CI, 5.2-22.3) compared to noninstrumented deliveries. The association was similar after adjustment for age, race, parity, mode of delivery, tobacco use, episiotomy, duration of labor (stages 1 and 2), infant birth weight, epidural, and oxytocin use (odds ratio, 11.9; 95% CI, 4.7-30.4). Nulliparous women were at increased risk for tears (adjusted odds ratio, 10.0; 95% CI, 3.0-33.3) compared with multiparous patients, but parity did not reduce the association between forceps-assisted deliveries and anal sphincter injuries. Increasing fetal weight was also a risk factor in both unadjusted and adjusted analyses. The performance of a midline episiotomy was associated with an increased risk of anal sphincter tear compared with delivery without an episiotomy in the univariate analysis (odds ratio, 4.9; 95% CI, 2.5-9.6), but this association was reduced in the adjusted analysis (odds ratio, 2.5; 95% CI, 1.0-6.0). The increased duration of both the first and second stages of labor increased injury risk in the unadjusted, but not adjusted, analysis. No significant association was observed between case status and the use of oxytocin or epidural anesthesia. Greater, but not significant, increased risk was associated with maternal indications for operative delivery compared with fetal indications. CONCLUSION: Our results are consistent with recent reports that identify forceps delivery and nulliparity as risk factors for recognized anal sphincter injury at the time of vaginal delivery. Further investigation should focus on the determination of whether the association of injury to instrumentation is causal or, in fact, modifiable. Because of the established association between sphincteric muscular damage and anal incontinence, patients should be counseled about the risk of anal sphincter injury when operative vaginal delivery is contemplated. Such patients should be followed closely in the postpartum setting to assess for the development of potential anorectal complaints.     

Is severe perineal damage increased in women with prior anal sphincter injury?

Objective.?There is conflicting data in the literature regarding the risk of obstetric anal sphincter laceration in patients with a prior laceration. This retrospective chart review seeks to examine the risk of recurrence of obstetric anal sphincter lacerations.

Methods.?Patients who sustained anal sphincter laceration at delivery during a 13-year time period from January 1991 to December 2003 were identified from the medical records database at Temple University Hospital. All subsequent deliveries in this group of patients were extracted from the database. Chart review was performed on all subsequent deliveries with specific attention to demographic factors such as age, race, parity, etc., maternal weight, fetal weight, presence of maternal diabetes, and labor characteristics such as induction or augmentation of labor, instrumentation at delivery (vacuum or forceps), use of episiotomy, and degree of perineal laceration.

Results.?There were 23 451 vaginal deliveries at Temple University Hospital between January 1, 1991 and December 31, 2003. Anal sphincter laceration was noted in 778 subjects. Subsequent deliveries among the group of patients with prior sphincter tears numbered 271. Six (2.4%) patients had recurrence of anal sphincter lacerations, and five of them were third degree lacerations. The rate of recurrent lacerations was not significantly different from the rate of initial lacerations (2.4% vs. 3.3%; odds ratio 0.72, 95% confidence interval 0.33–1.59; p = 0.4). Women who sustained recurrent lacerations were older, more obese (mean weight 92 kg vs. 82 kg), had larger babies (3506 g vs. 3227 g), and were more likely to have episiotomies (66.7% vs. 7%) or instrumental deliveries (33.3 vs. 6.5%).

Conclusion.?Prior anal sphincter laceration does not result in an increased rate of recurrence. Operative vaginal delivery particularly with episiotomy is a risk factor for both initial and recurrent laceration.     

Operative vaginal delivery and the use of episiotomy--a survey of practice in the United Kingdom and Ireland

OBJECTIVE: To establish the views and current practice of obstetricians with regard to operative vaginal delivery and the use of episiotomy. STUDY DESIGN: A national survey of consultant obstetricians and specialist registrars practising in the United Kingdom and Ireland registered with the Royal College of Obstetricians and Gynaecologists (RCOG), London. A postal questionnaire was sent to all obstetricians with two subsequent reminders to non-responders. The choice of procedure for specific circumstances, instrument preference, use of episiotomy and views on the relationship between episiotomy use and anal sphincter tears at operative vaginal delivery were explored. RESULTS: The response rate was 80.4%. Instrument preference varied according to the fetal position and station and the grade of operator. Vacuum and forceps were both used for mid-cavity non-rotational deliveries (64% and 56% reported frequent use respectively). Rotational vacuum was preferred for a mid-cavity mal-position (69%) followed by equal numbers using rotational forceps or manual rotation and forceps (34% and 36%, respectively). Inexperienced operators were more likely to proceed directly to caesarean section (35%). A restrictive approach to use of episiotomy was preferred for vacuum delivery (72%) and a routine approach for forceps (73%). Obstetricians varied greatly in their perception of the relationship between episiotomy use and anal sphincter tears at operative vaginal delivery. CONCLUSION: There is wide variation in the use of episiotomy at operative vaginal delivery with uncertainty about its role in preventing anal sphincter tears. A randomised controlled trial would address this important aspect of obstetric care.     

Episiotomy and perineal repair practices among obstetricians in Greece

Objective

To assess current preferences regarding episiotomy and management of obstetric perineal injuries used by obstetricians in Greece, and to assess the impact of evidence-based information on everyday practices.

Methods

A questionnaire survey of obstetricians regarding episiotomy use and the management of obstetric perineal injuries.

Results

Fifty-one percent of obstetricians reported routinely performing an episiotomy during a normal vaginal delivery in primiparous women and 89% reported performing an episiotomy during vacuum-assisted deliveries. Forty-two percent of the respondents performed lateral, 44% mediolateral, and 14% midline episiotomies. Following an obstetric anal sphincter tear, half of the respondents recommended a vaginal delivery, regardless of bowel symptoms. There was significant heterogeneity of practices regarding the repair techniques of all obstetric perineal injuries.

Conclusion

The majority of obstetricians prefer to perform routine mediolateral and lateral episiotomies, for both normal and operative vaginal deliveries. The adoption of evidence-based information should be implemented while considering working and cultural backgrounds.     

Risk factors for severe perineal tear: can we do better?

Our aim was to investigate the risk factors associated with severe perineal tears defined as either third- or forth-degree tears and, ultimately, find strategies for prevention. We carried a retrospective analysis of a computerized perinatal database, collected prospectively, from a single county hospital between January 1, 1993 and June 30, 1998. Singleton vaginal vertex deliveries were analyzed for potential risk factors using univariate and multiple logistic regression analysis including all two-way interactions. Severe perineal tear occurred in 1905 (8.2%) of 23,244 vaginal deliveries. In the multiple logistic regression analysis, the following factors carried a significantly higher risk for severe laceration: midline episiotomy, primary vaginal delivery, use of pudendal block, forceps deliveries, and birth weight more than 4000 g. The study of interactions demonstrated that mediolateral episiotomy was associated with an increased risk for severe tear only during the first vaginal delivery, but not during a repeat vaginal delivery. Our data suggest that primary vaginal delivery, fetal weight above 4000 g, and the use of pudendal analgesia can help identify in advance patients at highest risk for severe perineal tear. During the delivery of these patients usage of vacuum (instead of forceps) and restricting the use of midline episiotomy might reduce the incidence of severe perineal tear. In cases where episiotomy seems crucial, the use of a mediolateral episiotomy may reduce the likelihood of severe perineal tear.     

Instrumental delivery: clinical practice guidelines from the French College of Gynaecologists and Obstetricians

Routine use of a partograph is associated with a reduction in the use of forceps, but is not associated with a reduction in the use of vacuum extraction (Level A). Early artificial rupture of the membranes, associated with oxytocin perfusion, does not reduce the number of operative vaginal deliveries (Level A), but does increase the rate of fetal heart rate abnormalities (Level B). Early correction of lack of progress in dilatation by oxytocin perfusion can reduce the number of operative vaginal deliveries (Level B). The use of low-concentration epidural infusions of bupivacaine potentiated by morphinomimetics reduces the number of operative interventions compared with larger doses (Level A). Placement of an epidural before 3-cm dilatation does not increase the number of operative vaginal deliveries (Level A).Posterior positions of the fetus result in more operative vaginal deliveries (Level B). Manual rotation of the fetus from a posterior position to an anterior position may reduce the number of operative deliveries (Level C). Walking during labour is not associated with a reduction in the number of operative vaginal deliveries (Level A). Continuous support of the parturient by a midwife or partner/family member during labour reduces the number of operative vaginal deliveries (Level A). Under epidural analgesia, delayed pushing (2 h after full dilatation) reduces the number of difficult operative vaginal deliveries (Level A). Ultrasound is recommended if there is any clinical doubt about the presentation of the fetus (Level B).The available scientific data are insufficient to contra-indicate attempted midoperative delivery (professional consensus). The duration of the operative intervention is slightly shorter with forceps than with a vacuum extractor (Level C). Nonetheless, the urgency of operative delivery is not a reason to choose one instrument over another (professional consensus). The cup-shaped vacuum extractor seems to be the instrument of choice for operative deliveries of fetuses in a cephalic transverse position, and may also be preferred for fetuses in a posterior position (professional consensus). Vacuum extraction deliveries fail more often than forceps deliveries (Level B).Overall, immediate maternal complications are more common for forceps deliveries than vacuum extraction deliveries (Level B). Compared with forceps, operative vaginal delivery using a vacuum extractor appears to reduce the number of episiotomies (Level B), first- and second-degree perineal lesions, and damage to the anal sphincter (Level B). Among the long-term complications, the rate of urinary incontinence is similar following forceps, vacuum extraction and spontaneous vaginal deliveries (Level B). Anal incontinence is more common following forceps delivery (Level B). Persistent anal incontinence has a similar prevalence regardless of the mode of delivery (caesarean or vaginal, instrumental or non-instrumental), suggesting the involvement of other factors (Level B). Rates of immediate neonatal mortality and morbidity are similar for forceps and vacuum extraction deliveries (Level B). It appears that difficult instrumental delivery may lead to psychological sequelae that may result in a decision not to have more children (Level C). The rates of neonatal convulsions, intracranial haemorrhage and jaundice do not differ between forceps and vacuum extraction deliveries (Levels B and C).Rapid sequence induction with a Sellick manoeuvre (pressure to the cricoid cartilage) and tracheal intubation with a balloon catheter is recommended for any general anaesthesia (Level B).Training must ensure that obstetricians can identify indications and contra-indications, choose the appropriate instrument, use the instruments correctly, and know the principles of quality control applied to operative vaginal delivery. Nowadays, traditional training can be accompanied by simulations. Training should be individualized and extended for some students.     

Delivery method, anal sphincter tears and fecal incontinence: new information on a persistent problem

PURPOSE OF REVIEW: To review the risk factors for anal sphincter tears during vaginal delivery and their association with fecal incontinence symptoms. RECENT FINDINGS: Recent evidence links sphincter tears with fecal incontinence, which has a significant negative impact on quality of life. The Childbirth and Pelvic Symptoms cohort study reported that the incidence and severity of fecal incontinence was increased in primiparous women experiencing a sphincter tear. Risk factors for tear included forceps, occiput posterior, vacuum delivery, prolonged second stage of labor and epidural. Using cesarean delivery to prevent fecal incontinence has not been justified, but the confluence of these risk factors in the context of labor management may be important in deciding on earlier intervention with cesarean delivery. Internal anal sphincter defects impact fecal incontinence, highlighting the identification and repair of the internal anal sphincter for future research and clinical applications. Routine episiotomy (or instrumentation) is not warranted, and there is no clear advantage to mediolateral episiotomy or overlapping sphincter repair. Postpartum ultrasound of the sphincter complex may have an emerging role. SUMMARY: The modifiable risk factors of routine episotomy and instrumented delivery are associated with sphincter tear; definitive recommendations for labor management remain unclear in preventing fecal incontinence.     

The role of mediolateral episiotomy during labour: analysis of risk factors for obstetric anal sphincter tears

BACKGROUND: To determine risk factors for third-degree and complete third- or fourth-degree anal sphincter tears in vaginal delivery. METHODS: This is a retrospective comparative study. Fifty-three women who had sustained an anal sphincter tear were compared with 9,178 women without such a complication between August 1997 and October 2001. Obstetric data was collected from an electronic database. The main outcome measures were odds ratios. RESULTS: In the whole study population, odds ratios (ORs) for third-degree tears were: primiparity, 8.34 (95% confidence interval [CI] 3.98-17.48); vacuum extraction, 5.22 (95% CI 2.69-10.13); parietal presentation, 3.97 (95% CI 1.16-13.64); and birth weight >4,000 g, 3.77 (95% CI 2.11-6.68); and for complete third- or fourth-degree tears odds ratios were 5.42, 2.98, 5.64, and 3.01, respectively. In multivariate analysis, mediolateral episiotomy appeared to be protective as regards third-degree tears (OR 0.37 [95% CI 0.2020-0.70]). CONCLUSIONS: Vacuum-assisted vaginal delivery bears an increased risk of third-degree anal sphincter tears in a maternity unit where forceps are not used. Restricted use of mediolateral episiotomy may have a protective effect on the perineum.     

Could a mediolateral episiotomy prevent obstetric anal sphincter injury?

Objective

To analyse the significance of risk factors and the role of episiotomy in preventing obstetric anal sphincter injury at vaginal delivery.

Study design

This is a retrospective cross-sectional study in the Norfolk and Norwich University Hospital in the UK. All caesarean sections and non-vertex presentations were excluded, which resulted in a study population of 10,314 deliveries. Obstetric anal sphincter injury (OASI) was defined as third or fourth degree tears to the anal sphincter muscles, with or without a tear involving the anal mucosa. First a univariate analysis was done to identify factors that had a significant association with OASI. Factors included parity, age, gestation, labour induction method, duration of second stage, use of epidural analgesia, episiotomy, method of delivery, time and month of delivery, and birth weight. All factors were then combined in a multivariate logistic regression analysis. The multivariate analysis was then repeated including only factors that had a significant association with OASI in the univariate analysis. Adjusted odds ratios with 95% confidence intervals (CI) were calculated.

Results

The frequency of anal sphincter lacerations was 3.2%. There were statistically significant associations between an increased incidence of OASI and parity, birth weight, method of delivery and shoulder dystocia. Women giving birth without a mediolateral episiotomy were 1.4 times more likely to experience OASI (95% CI 1.021–1.983). Interestingly, the incidence of OASI has risen between 2005 and 2007.

Conclusion

Parity, age, birth weight, method of delivery and shoulder dystocia are strongly associated with obstetric anal sphincter injury. Mediolateral episiotomy appears to be protective against OASI but a randomised controlled trial would be needed to confirm this. The rising incidence of OASI after normal vaginal deliveries may be related to adoption of the hands off technique or increased identification of tears.     

Obstetric anal sphincter lacerations

OBJECTIVE: To estimate the frequency of obstetric anal sphincter laceration and to identify characteristics associated with this complication, including modifiable risk factors. METHODS: A population-based, retrospective study of over 2 million vaginal deliveries at California hospitals was performed, using information from birth certificates and discharge summaries for 1992 through 1997. We excluded preterm births, stillbirths, breech deliveries, and multiple gestations. The main outcome measure was obstetric anal sphincter laceration (third and fourth degree). RESULTS: The frequency of anal sphincter lacerations was 5.85% (95% confidence interval [CI] 5.82, 5.88), decreasing significantly from 6.35% (95% CI 6.27, 6.43) in 1992 to 5.43% (95% CI 5.35, 5.51) in 1997 (P <.01). Using logistic regression analysis, we identified primiparity as the dominant risk factor (odds ratio [OR] for women with prior vaginal birth 0.15; 95% CI 0.14, 0.15). Birth weight over 4000 g was also highly significant (OR 2.17; 95% CI 2.07, 2.27). Lacerations occurred more often among women of certain racial and ethnic groups: Indian women (OR 2.5; 95% CI 2.23, 2.79) and Filipina women (OR 1.63; 95% CI 1.50, 1.77) were at highest risk. Episiotomy decreased the likelihood of third-degree lacerations (OR 0.81; 95% CI 0.78, 0.85), but increased the risk of fourth-degree lacerations (OR 1.12; 95% CI 1.05, 1.19). Operative delivery increased the risk of sphincter laceration, with vacuum delivery (OR 2.30; 95% CI 2.21, 2.40) presenting a greater risk than forceps delivery (OR 1.45; 95% CI 1.37, 1.52). CONCLUSION: Anal sphincter lacerations are strongly associated with primiparity, macrosomia, and operative vaginal delivery. Of the modifiable risk factors, operative vaginal delivery remains the dominant independent variable.     

Intervention during labor: risk factors associated with complete tear of the anal sphincter.

Among 41,200 consecutive deliveries there were 152 cases of complete tear of the anal sphincter (complete tear). In a case-control design, the association between interventions during labor (forceps, vacuum extraction, use of oxytocin and prostaglandins and mediolateral episiotomy) and complete tear, were evaluated by confounder control using multiple logistic regression analysis. Controls chosen were the patients delivering just before and after the index patient with complete tear. Use of Kielland forceps, mediolateral episiotomy, shoulder dystocia and nulliparity were significantly associated with complete tear. Maternal age, presentation in labor, duration of second stage of labor and the indication for instrumental deliveries and episiotomy had no significant association with complete tear.     

Pelvic floor disorders 4 years after first delivery: a comparative study of restrictive versus systematic episiotomy

Objective  To compare two policies for episiotomy: restrictive and systematic.
Design  Quasi-randomised comparative study.
Setting  Two French university hospitals with contrasting policies for episiotomy: one using episiotomy restrictively and the second routinely.
Population  Seven hundred and seventy-four nulliparous women delivered during 1996 of a singleton in cephalic presentation at a term of 37–41 weeks.
Methods  A questionnaire was mailed 4 years after delivery. Sample size was calculated to allow us to show a 10% difference in the prevalence of urinary incontinence with 80% power.
Main outcome measures  Urinary incontinence, anal incontinence, perineal pain, and pain during intercourse.
Results  We received 627 responses (81%), 320 from women delivered under the restrictive policy, 307 from women delivered under the routine policy. In the restrictive group, 186 (49%) deliveries included mediolateral episiotomies and in the routine group, 348 (88%). Four years after the first delivery, there was no difference in the prevalence of urinary incontinence (26 versus 32%), perineal pain (6 versus 8%), or pain during intercourse (18 versus 21%) between the two groups. Anal incontinence was less prevalent in the restrictive group (11 versus 16%). The difference was significant for flatus (8 versus 13%) but not for faecal incontinence (3% for both groups). Logistic regression confirmed that a policy of routine episiotomy was associated with a risk of anal incontinence nearly twice as high as the risk associated with a restrictive policy (OR = 1.84, 95% CI: 1.05–3.22).
Conclusions  A policy of routine episiotomy does not protect against urinary or anal incontinence 4 years after first delivery.