Risk of recurrence of anal sphincter lacerations

OBJECTIVE: To estimate the rate of recurrence of anal sphincter lacerations in subsequent pregnancies and analyze the risk factors associated with recurrent lacerations METHODS: Data were obtained from the Pennsylvania Health Care Cost Containment Council, Division of In-Patient Statistics, regarding all cases of third- and fourth-degree perineal lacerations that occurred during a 2-year period (from January 1990 through December 1991). All subsequent pregnancies in this group of women over the next 10 years were identified, and the rate of recurrence of sphincter tears and risk factors for recurrence were analyzed. RESULTS: The rate of anal sphincter lacerations was 7.31% (n = 18,888) during the first 2 years of study (1990-1991). In the next 10 years, these patients with prior lacerations were delivered of 16,152 pregnancies. Of these, 1,162 were by cesarean. Among the 14,990 subsequent vaginal deliveries, 864 (5.76%) had a recurrence of a third- or fourth-degree laceration. Women with prior fourth-degree lacerations had a much higher rate of recurrence than those with prior third-degree laceration (7.73% versus 4.69%). The rate for recurrent lacerations was significantly lower than the rate for initial lacerations (odds ratio 1.29, 95% confidence interval [CI] 1.2-1.4). Forceps delivery with episiotomy had the highest risk for recurrent laceration (17.7%, odds ratio 3.6, 95% CI 2.6-5.1), whereas vacuum use without episiotomy had the lowest risk (5.88%, odds ratio 1.0, 95% CI 0.6-1.7). CONCLUSION: Prior anal sphincter laceration does not appear to be a significant risk factor for recurrence of laceration. Operative vaginal delivery, particularly with episiotomy, increases the risk of recurrent laceration as it does for initial laceration. LEVEL OF EVIDENCE: III.     

Fecal and urinary incontinence after vaginal delivery with anal sphincter disruption in an obstetrics unit in the United States

OBJECTIVE: The purpose of this study was to estimate the incidence of urinary and bowel incontinence in relation to anal sphincter laceration in primiparous women and to identify factors that are associated with anal sphincter laceration in a unit that uses primarily midline episiotomy. STUDY DESIGN: From January 1, 1997, to March 30, 2000, 2941 questionnaires concerning pelvic floor function 6 months after delivery were mailed to primiparous women who were delivered vaginally at the University of Michigan Medical Center. Charts were reviewed for 2858 deliveries to assess the use of episiotomy and the degree of perineal trauma, along with demographic and pertinent delivery variables. There were 943 women who completed the urinary function questionnaire and 831 women who completed the bowel function questionnaire. Univariate analysis was performed on all covariates. Multiple logistic regression was used for the analysis of the presence of third- or fourth-degree lacerations as the outcome. RESULTS: Nineteen percent of the women who completed the survey had sustained third- or fourth-degree lacerations during childbirth. The women in the sphincter laceration group were more likely (23.0%) to have bowel incontinence than the women in the control group (13.4%) (P<.05). The incidence of worse bowel control was nearly 10 times higher in women with fourth-degree lacerations (30.8%) compared with women with third-degree lacerations (3.6%, P<.001). Macrosomia (odds ratio, 2.19; 95% CI, 1.61, 2.99), forceps-assisted delivery (odds ratio, 4.75; 95% CI, 3.43, 6.57), and vacuum-assisted delivery (odds ratio, 3.51; 95% CI, 2.64, 4.66) were associated with higher risks of third- and fourth-degree lacerations. Midline episiotomy (odds ratio, 2.24; 95% CI, 1.81, 2.77), but not mediolateral (odds ratio, 0.66; 95% CI, 0.375, 1.19), episiotomy was associated with anal sphincter lacerations. More than one half of the women had new onset of urinary incontinence after delivery and reported several lifestyle modifications to prevent leakage. CONCLUSION: Women with third- and fourth-degree lacerations were more likely to have bowel incontinence than women without anal sphincter lacerations. Fourth-degree lacerations appear to affect anal continence greater than third-degree lacerations.     

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.     

Occiput posterior fetal head position increases the risk of anal sphincter injury in vacuum-assisted deliveries

OBJECTIVE: The purpose of this study was to determine whether an occiput posterior (OP) fetal head position increases the risk for anal sphincter injury when compared with an occiput anterior (OA) position in vacuum-assisted deliveries. STUDY DESIGN: We conducted a retrospective cohort study of 393 vacuum-assisted singleton vaginal deliveries. Maternal demographics and obstetric and neonatal data were collected from an obstetric database and chart review. RESULTS: Within the OP group, 41.7% developed a third- or fourth-degree laceration compared with 22.0% in the OA group (OR 2.5, 95% CI 1.4-4.7). In a logistic regression model that controlled for BMI, race, nulliparity, length of second stage, episiotomy, birth weight, head circumference, and fetal head position, OP position was 4.0 times (95% CI 1.7-9.6) more likely to be associated with an anal sphincter injury than OA position. CONCLUSION: Among vacuum deliveries, an OP head position confers an incrementally increased risk for anal sphincter injury over an OA position.     

The effect of epidural analgesia on rates of episiotomy use and episiotomy extension in an inner-city hospital

Objective : To determine the relationship between epidural analgesia and episiotomy usage and episiotomy extension in parturients delivering vaginally. Methods : A database of 20 888 women experiencing spontaneous vaginal delivery at Grady Memorial Hospital from 1990 to 1995 was examined to identify those receiving epidural analgesia. Patients who underwent epidural catheter placement and had adequate perineal anesthesia at delivery comprised the epidural group, and all others comprised the control group. Demographic characteristics and obstetric outcomes were compared. Univariate and multivariate analyses were used to test the association between epidural analgesia, rates of episiotomy and episiotomy extension. Results : Of the 20 888 women experiencing spontaneous vaginal deliveries 6785 (32.5%) received epidural analgesia. Women receiving epidural analgesia were more likely than those not receiving epidural analgesia to be African-American and nulliparous, and to have an occiput posterior presentation. Women receiving epidural analgesia were also more likely to receive an episiotomy (27.8% vs. 13.1%, odds ratio (OR) 2.56, 95% confidence interval (CI) 2.38-2.75) and were less likely to experience a second-degree perineal laceration (11.6% vs. 14.4%, OR 0.75, 95% CI 0.69-0.82) or a third- or fourth-degree extension (8.9% vs. 12.4%, OR 0.81, 95% CI 0.68-0.97). When the results were adjusted for nulliparity, posterior presentation, macrosomia, shoulder dystocia and prolonged second stage, epidural analgesia remained independently associated with receipt of episiotomy (OR 1.97, 95% CI 1.88-2.06) and reduced episiotomy extension (OR 0.74, 95% CI 0.54-0.94). Conclusion : Epidural analgesia increases the rates of episiotomy use, and decreases the rate of episiotomy extension, independently of clinical factors associated with episiotomy.     

The effect of epidural analgesia on rates of episiotomy use and episiotomy extension in an inner-city hospital

OBJECTIVE: To determine the relationship between epidural analgesia and episiotomy usage and episiotomy extension in parturients delivering vaginally. METHODS: A database of 20 888 women experiencing spontaneous vaginal delivery at Grady Memorial Hospital from 1990 to 1995 was examined to identify those receiving epidural analgesia. Patients who underwent epidural catheter placement and had adequate perineal anesthesia at delivery comprised the epidural group, and all others comprised the control group. Demographic characteristics and obstetric outcomes were compared. Univariate and multivariate analyses were used to test the association between epidural analgesia, rates of episiotomy and episiotomy extension. RESULTS: Of the 20888 women experiencing spontaneous vaginal deliveries 6785 (32.5%) received epidural analgesia. Women receiving epidural analgesia were more likely than those not receiving epidural analgesia to be African-American and nulliparous, and to have an occiput posterior presentation. Women receiving epidural analgesia were also more likely to receive an episiotomy (27.8% vs. 13.1%, odds ratio (OR) 2.56, 95% confidence interval (CI) 2.38-2.75) and were less likely to experience a second-degree perineal laceration (11.6% vs. 14.4%, OR 0.75, 95% CI 0.69-0.82) or a third- or fourth-degree extension (8.9% vs. 12.4%, OR 0.81, 95% CI 0.68-0.97). When the results were adjusted for nulliparity, posterior presentation, macrosomia, shoulder dystocia and prolonged second stage, epidural analgesia remained independently associated with receipt of episiotomy (OR 1.97, 95% CI 1.88-2.06) and reduced episiotomy extension (OR 0.74, 95% CI 0.54-0.94). CONCLUSION: Epidural analgesia increases the rates of episiotomy use, and decreases the rate of episiotomy extension, independently of clinical factors associated with episiotomy.     

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.     

Racial differences in severe perineal lacerations after vaginal delivery

OBJECTIVE: The purpose of this study was to determine the relationship between maternal race and rates of third- and fourth-degree laceration after vaginal delivery. STUDY DESIGN: An electronic audit of the medical procedures database at Thomas Jefferson University Hospital from 1983 through 2000 was completed. Univariate and multivariable models were computed with the use of logistic regression models. RESULTS: From the database, 34,048 vaginal deliveries were identified, with 3487 deliveries resulting in third- or fourth-degree laceration (10.2%). Overall severe laceration rates by race with all vaginal deliveries for patients without and with episiotomy were as follows: white, 4.3% and 15.1%; black, 2.0% and 19.3%; Asian 9.1% and 32.3%; Hispanic, 3.4% and 17.0%, respectively. After being controled for other variables with multivariable logistic regression in all vaginal deliveries, Asian race (odds ratio, 2.04; 95% CI, 1.43-2.92), forceps (odds ratio, 3.71; 95% CI, 3.39-4.05), vacuum-assisted delivery (odds ratio, 1.86; 95% CI, 1.64-2.10), large size for gestational age (odds ratio, 1.94; 95% CI, 1.21-3.09), and episiotomy (odds ratio, 3.09; 95% CI, 2.66-3.59) were associated significantly with severe lacerations. CONCLUSION: Race is an independent risk factor for severe perineal lacerations after vaginal delivery, with Asian women at highest risk. Asian women who undergo episiotomy and operative vaginal delivery are especially at high risk for rectal sphincter injury.     

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.     

Prior third- or fourth-degree perineal tears and recurrence risks.

OBJECTIVE: The objective of the present study is to determine the recurrence risk of a third-degree (into the anal sphincter) or a fourth-degree (into the rectum) perineal tear in women with a prior extensive laceration. METHODS: Data were gathered from our computerized perinatal database between January 1990 and December 1994. Women who had two consecutive singleton deliveries were chosen as subjects. RESULTS: The rate of an extensive perineal laceration was greater if a tear had occurred in a previous pregnancy (19 of 178 cases, 10.7% vs. 56% of 1563 cases, 3.6%, odds ratio 3.4. A 95% confidence interval: 1.8-6.4; p < 0.0001). A prior tear remained a risk factor after controlling for other variables (epidural analgesia, episiotomy, oxytocin use, operative vaginal delivery, fetal macrosomia). CONCLUSION: A prior third-degree or fourth-degree perineal tear is associated with a 3.4-fold increased risk of a recurrent severe obstetrical laceration.     

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 anal sphincter tear during vaginal delivery

OBJECTIVE: To identify risk factors associated with anal sphincter tear during vaginal delivery and to identify opportunities for preventing this cause of fecal incontinence in young women. METHODS: We used baseline data from two groups of women who participated in the Childbirth and Pelvic Symptoms (CAPS) study: those women who delivered vaginally, either those with or those without a recognized anal sphincter tear. Univariable analyses of demographic and obstetric information identified factors associated with anal sphincter tear. We calculated odds ratios (ORs) for these factors alone and in combination, adjusted for maternal age, race, and gestational age. RESULTS: We included data from 797 primaparous women: 407 with a recognized anal sphincter tear and 390 without. Based on univariable analysis, a woman with a sphincter tear was more likely to be older, to be white, to have longer gestation or prolonged second stage of labor, to have a larger infant (birth weight/head circumference), or an infant who was in occiput posterior position, or to have an episiotomy or operative delivery. Logistic regression found forceps delivery (OR 13.6, 95% confidence interval [CI] 7.9-23.2) and episiotomy (OR 5.3, 95% CI 3.8-7.6) were strongly associated with a sphincter tear. The combination of forceps and episiotomy was markedly associated with sphincter tear (OR 25.3, 95% CI 10.2-62.6). The addition of epidural anesthesia to forceps and episiotomy increased the OR to 41.0 (95% CI 13.5-124.4). CONCLUSION: Our results highlight the existence of modifiable obstetric interventions that increase the risk of anal sphincter tear during vaginal delivery. Our results may be used by clinicians and women to help inform their decisions regarding obstetric interventions. LEVEL OF EVIDENCE: II.     

Anal sphincter tears at vaginal delivery: risk factors and clinical outcome of primary repair.

OBJECTIVE: To determine risk factors for obstetric anal sphincter tears and to evaluate symptomatic outcome of primary repair. METHODS: Obstetric-procedure, maternal, and fetal data were registered in 845 consecutive vaginally delivered women. Risk factors for anal sphincter tears were calculated by multiple logistic regression. All 808 Swedish-speaking women who delivered vaginally were included in a questionnaire study regarding anal incontinence in relation to the delivery. Questionnaires were distributed within the first few days postpartum, and at 5 and 9 months postpartum. RESULTS: Six percent of the women had a clinically detected sphincter tear at delivery. Sphincter tears were associated with nulliparity (odds ratio [OR] 9.8, 95% confidence interval [CI] 3.6, 26.2), postmaturity (OR 2.5, 95% CI 1.0, 6.2), fundal pressure (OR 4.6 95% CI 2.3, 7.9), midline episiotomy (OR 5.5 95% CI 1.4,18.7), and fetal weight in intervals of 250 g (OR 1.3 95% CI 1.1, 1.6). Fifty-four percent of women with repaired sphincter tears suffered from fecal or gas incontinence or both at 5 months and 41% at 9 months. Most of the symptoms were infrequent and mild. CONCLUSION: Several risk factors for sphincter tear were identified. Sphincter tear at vaginal delivery is a serious complication, and it is frequently associated with anal incontinence. Special attention should be directed toward risk factors for this complication. Symptoms of anal incontinence should explicitly be sought at follow-up after delivery.     

Recurrent risk of anal sphincter laceration among women with vaginal deliveries

OBJECTIVE: The first aim of this study was to estimate the impact of anal sphincter laceration during the first delivery on the risk of recurrence in the second delivery. The second aim was to estimate the absolute risk of anal sphincter laceration in the second delivery according to the history of anal sphincter laceration and birth weight. METHODS: In this population-based cohort study, the study sample comprised all women included in the Norwegian Medical Birth Registry with 2 consecutive singleton vaginal deliveries during the period 1967-1998 (n = 486,463). The impact of prior anal sphincter laceration on recurrent anal sphincter laceration was estimated as crude and adjusted odds ratios (ORs). RESULTS: Anal sphincter laceration during first delivery increased the risk for a sphincter laceration in the next delivery, (adjusted OR 4.3, 95% confidence interval [CI] 3.8-4.8). Other risk factors were birth weight (adjusted OR 23.6, 95% CI 16.5-33.6, birth weight > 5,000 g versus birth weight < 3,000 grams), use of forceps (adjusted OR 5.1, 95% CI 4.3-6.0), use of vacuum (adjusted OR 1.4, 95% CI 1.1-1.7), and period of delivery (adjusted OR 4.3, 95% CI 3.7-5.0 for 1995-1998 versus 1967-1975). The absolute risks for anal sphincter laceration at second delivery for women with prior laceration were 1.3% (95% CI 0.4-3.2%) for birth weight less than 3,000 g and 23.3% (95% CI 11.8-38.6%) for birth weight more than 5,000 g. CONCLUSION: Only 10% of women with anal sphincter laceration at second delivery had a history of prior laceration. Prior anal sphincter laceration is associated with increased risk of laceration in second delivery, in particular in women who carry children with high birth weight. LEVEL OF EVIDENCE: II-2.     

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.     

Predictors of episiotomy use at first spontaneous vaginal delivery

OBJECTIVE: To identify factors associated with the use of episiotomy at spontaneous vaginal delivery. METHODS: We studied 1576 consecutive term, singleton, spontaneous vaginal deliveries in nulliparas at Brigham & Women's Hospital between December 1, 1994 and July 31, 1995. The association of demographic variables and obstetric factors with the rate of episiotomy use were examined. Adjusted odds ratios (OR) and confidence intervals (CI) were estimated from multiple logistic regression analysis. RESULTS: The overall rate of episiotomy was 40.6% (640 of 1576). Midwives performed episiotomies at a lower rate (21.4%) than faculty (33.3%) and private providers (55.6%) (P =. 001). After controlling for confounding factors with logistic regression, private practice provider was the strongest predictor of episiotomy use (OR, 4.1; 95% CI, 3.1, 5.4) followed by faculty provider (OR, 1.7; 95% CI, 1.1, 2.5), prolonged second stage of labor (OR, 1.8; 95% CI, 1.2, 2.7), fetal macrosomia (OR, 1.6; 95% CI, 1.1, 2.5), and epidural analgesia (OR 1.4, 95% CI, 1.1, 1.8). CONCLUSION: The strongest factor associated with episiotomy at delivery was the category of obstetric provider. Obstetric and demographic factors evaluated did not readily explain this association.     

Trends in major modifiable risk factors for severe perineal trauma, 1996–2006

OBJECTIVE: To examine what effect the major modifiable risk factors for severe perineal trauma have had on the rates of this trauma over time. METHODS: A retrospective observational cohort study of singleton vaginal deliveries taken from a perinatal database for the period 1996 through 2006. RESULTS: A total of 46,239 singleton vertex vaginal deliveries met the inclusion criteria. Major risk factors for severe perineal trauma were increased maternal age (odds ratio [OR] 1.28, 95% confidence interval [CI] 1.1-1.5), non-African American ethnicity (OR 1.5, 95% CI 1.3-1.7), nulliparity (OR 4.8, 95% CI 4.11-5.6), fetal birth weight (OR 2.2, 95% CI 1.9-2.4), forceps (OR 8.3, 95% CI 5.4-10.8), vacuum (OR 2.9, 95% CI 1.9-4.4), and midline episiotomy (OR 5.7, 95% CI 5.0-6.4). Evaluation of the changes in rates of these factors over the study period revealed that the decline in the rates of episiotomy and the use of forceps accounted for a reduction in severe lacerations of more than 50%. CONCLUSION: Reduction of severe perineal trauma by restricted use of the 2 modifiable clinical variables, episiotomy and forceps, is evident over time.     

Maternal Ethnicity and the Risk of Obstetrical Anal Sphincter Injury: A Retrospective Cohort Study

ObjectiveTo explore the role of maternal ethnicity as a risk factor for obstetrical anal sphincter injury (OASI).MethodsA retrospective cohort study of all women with singleton gestations who had a vaginal delivery at term, between January 2014 and October 2017, at a single center. OASI was defined as a third-degree perineal tear (anal sphincter complex) or a fourth-degree perineal tear (anorectal mucosa). The characteristics of women with and without OASIs were compared. Multiple logistic regression was performed to account for potential confounders, including ethnicity.ResultsDuring the study period, 11 012 women were eligible for inclusion, of whom 336 (3.1%) had an OASI; 313 (93.1%) had a third-degree tear, and 23 (6.9%) had a fourth-degree tear. Women with OASIs were characterized by younger maternal age (<35 years), Asian ethnicity, nulliparity, neonatal birth weight ≥3500 grams, midline and mediolateral episiotomy, second stage of labour lasting ≥60 minutes, and assisted vaginal delivery. After adjusting for potential confounders, Asian ethnicity remained independently associated with increased risk of OASI (adjusted odds ratio 2.07; 95% CI 1.6–2.7) whereas mediolateral episiotomy was independently associated with decreased risk of OASI (adjusted odds ratio 0.64; 95% CI 0.5–0.9).ConclusionAsian ethnicity is independently associated with increased risk of OASI. Although midline episiotomy increases the risk of OASI, mediolateral episiotomy may protect against OASI, and should be considered in high-risk patients.     

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.     

Third and fourth degree perineal tears. Predictor factors in a referral hospital

BACKGROUND: Tears of the anal sphincter are a feared complication of vaginal delivery, as many as 50% of these patients experience incontinence as an after-effect. Identifying significant predictor factors leading to third or fourth degree perineal tears during vaginal delivery was the objective of this study. METHODS: During a two-year period (1995-1996), a third or fourth degree perineal rupture occurred in 214 women (3.7%) after vaginal delivery. Data from these deliveries were collected and compared to data from deliveries without anal sphincter tears in order to identify risk factors. A stepwise logistic regression model was used for the analysis. RESULTS: Independent risk factors of significance were vaginal nulliparity, a squatting position on a delivery chair, maternal age exceeding 35 years, baby's birth weight over 4000 g, vacuum extraction (both outlet and mid release), median episiotomy, oxytocin augmentation and birthing between 3 a.m. and 6 a.m. CONCLUSIONS: This study identified several factors associated with anal sphincter tears. Median episiotomy should be avoided. Delivery, while squatting on a low chair, should be used with caution. A woman with one or more risk factors requires caution by birth attendants during delivery. Gynecologists should consider the option of cesarean section instead of vacuum extraction, especially when mid release is needed in the presence of macrosomia. A continuous audit regarding instrumental delivery technique is necessary.