Volume 198, Issue 3 , Pages 285.e1-285.e4, March 2008
Selective vs routine midline episiotomy for the prevention of third- or fourth-degree lacerations in nulliparous women
Article Outline
Objective
The purpose of this study was to determine whether selective midline episiotomy contributes to the prevention of third- or fourth-degree perineal lacerations.
Study Design
A randomized controlled clinical trial was performed with 446 nulliparous women with deliveries after 28 weeks of pregnancy. Patients were randomized to undergo either routine episiotomy or selective episiotomy. In the selective episiotomy group, episiotomies were performed only in cases of imminent lacerations, fetal distress, or forceps delivery.
Results
In the group of 223 patients who underwent routine episiotomy, 32 (14.3%) had third- or fourth-degree perineal lacerations, as compared to 15 (6.8%) in the group of 222 patients undergoing selective episiotomy (relative risk, 2.12; 95% confidence interval, 1.18-3.81). Only reduction in third-degree lacerations was significant when analyzed separately. Moreover, periurethral, labia minora, and superficial vaginal lacerations were significantly more frequent in the selective episiotomy group.
Conclusion
The policy of performing selective midline episiotomy in nulliparous patients results in a reduction in the risk of third-degree perineal lacerations.
Key words: episiotomy, perineal laceration
Historically, the liberal use of episiotomy was common when caring for nulliparous women in order to prevent complications for the mother (deep perineal lacerations, relaxation of the pelvic floor) as well as for the fetus (fetal hypoxia, shoulder retention).1, 2 With the publication of several descriptive and analytical papers assessing the effectiveness of episiotomy in preventing deep perineal lacerations (third and fourth degree), it was determined that, paradoxically, instead of playing a protective role for those events, episiotomy actually favored their occurrence.3 This creates concerns about the associated morbidity, including pain, bleeding, infection, rectovaginal fistulas, fecal or flatus incontinence, and intercourse disruption.3, 4, 5, 6, 7, 8, 9, 10 Most of these studies assessed mediolateral episiotomies10 and several schools, including ours, have traditionally performed and taught midline episiotomy.2
There is a shortage of world literature regarding midline episiotomy. In a recent metaanalysis of the Cochrane collaboration, of the 6 studies included, only 1 of them described the use of a midline technique.11 The remaining studies used the mediolateral technique, including a collaborative Argentine study with the largest number of patients.10 The systematic review in 2005 included basically the same studies found in the Cochrane analysis.12
We performed a prospective, randomized clinical trial to determine whether selective midline episiotomy is associated with the prevention of third- or fourth-degree perineal lacerations in nulliparous women.
Materials and Methods
The patients were nulliparous women with pregnancies more than 28 weeks of gestation who had vaginal deliveries. Women with multiple pregnancies were excluded, as were patients with breech presentations and those who did not sign the informed consent or refused to participate in the study.
The randomized study was performed at San Vicente de Paul teaching hospital, a high complexity care level institution in Medellín-Antioquia with an average of 1200 deliveries per year; and the Hospital del Sur, a mid-complexity care level institution caring for an average of 800 deliveries per year in Itagui-Antioquia.
Ralloc software (Boston College Department of Economics, Boston, MA) was used to create a random sequence of numbers in blocks with 2, 4, and 6 size permutations. Informed consent was obtained when it was determined that a patient fulfilled the requirements to enter the study; the consent form to enroll in the study was processed during the first stage of labor. All the patients in this study were informed of the benefits and risk of the episiotomy. Despite the evidence available in the literature, in our country, midline episiotomy is still a medical procedure commonly performed in nulliparous patients. For this reason we still considered the study to be ethical. An increase in the possibility of third- and fourth-degree lacerations and the lack of evidence regarding benefits for the pelvic floor after the making of the episiotomy was also discussed. The patients were taken to the delivery room where they received routine care. Upon admission during the second stage of labor, patients were assigned either to the routine episiotomy or the selective episiotomy group, depending of the basis of the randomization sequence kept at the institution.
The ethics board of the San Vicente de Paul University Hospital, which works as the institutional review board (IRB), granted its approval.
The episiotomy consisted of an incision of approximately 4 cm over the midline of the perineum, from the introitus to the rectum, including skin, subcutaneous cellular tissue, superficial fascia, and perineal muscle, followed by a 4-6 cm incision of the vaginal mucosa, under local anesthesia with lidocaine without epinephrine.
The primary outcome of severe laceration to perineal tissues was defined as a third-degree laceration when the extent of the lesion included the external anal sphincter totally or partially, and fourth-degree laceration when the rectal mucosa was involved.
The objective was to find a significant reduction from 15% down to 6% in the incidence of third- or fourth-degree lacerations. In order to achieve an 80% power for finding such differences with an alpha error of 5%, it was estimated that 203 women were required for each group. To compensate for the possibility of patients leaving the study, we then projected a 10% increase in the sample size to finally include 223 patients in each group.
Patients assigned to the selective episiotomy group underwent the procedure only in cases of forceps delivery, fetal distress, or shoulder dystocia or when the operator considered that a severe laceration was impending and could only be avoided by performing an episiotomy. This decision was made by the treating physician. All the patients in the routine episiotomy group underwent the procedure at the time the fetal head was distending the introitus. The deliveries were assisted by obstetrics and gynecology residents or by the obstetrician on call. In our city, the vacuum is not employed.
After the delivery, the perineum was examined to determine the presence of lateral, anterior, superficial or deep vaginal lacerations, and posterior lacerations classified as first-degree to fourth-degree according to the currently accepted classification.1
Statistical analysis
The distribution of continuous variables was assessed using the Kolmogorov–Smirnov test. Continuous variables with a normal distribution were summarized using the mean plus standard deviation. The Student t test was used for comparing population characteristics for the normally distributed continuous variables. Categorical variables were expressed as percentages. The χ2 test was used for comparing categorical variables. Results are presented in the form of relative risk (RR) with their respective 95% confidence interval (95% CI). The analysis was performed using the SPSS 11.5 statistical software package (SPSS, Chicago, IL).
Results
Between February 2002 and November 2004, 446 patients were randomly assigned to 2 groups of 223 patients each. One patient was excluded from the selective episiotomy group because she failed to fulfill the inclusion criteria (gestational age <28 weeks). All the 223 patients in the routine episiotomy group underwent midline episiotomy, as well as 54 patients in the selective episiotomy group. During the same study period, 279 deliveries of nulliparous women were cared for at the Southern Hospital and 167 at the St. Vincent Paul Hospital. There are no statistically significant differences in any of the patient characteristics between the 2 arms (Table 1).
TABLE 1. General characteristics of the study population
| Routine episiotomy n = 223 | Selective episiotomy n = 222 | |
|---|---|---|
| Age (y) | 19.7 ±4.0 | 19.8±4.1 |
| Gestational age (wk) | 38.0±2.1 | 38.0±2.1 |
| Birth weight (g) | 2936±470 | 2899±481 |
| Mean head circumference (cm) | 33.3±1.5 | 33.1±1.5 |
| Oxytocin use | 142(63.7) | 149(67.1) |
| Forceps use | 4(1.8) | 3(1.4) |
| Epidural use | 40(17.9) | 37(16.7) |
| Prolonged delivery | 5(2.2) | 13(5.9) |
In the routine episiotomy group 22 (9.9%) developed third-degree lacerations compared to 10 (4.5%) of patients in the selective episiotomy group (RR, 2.19; 95% CI, 1.06-4.52). There was no significant difference between the frequency of fourth-degree lacerations with 4.5% and 2.3% in the routine vs selective groups (Table 2).
TABLE 2. Perineal injury outcomes of routine vs selective episiotomy
| Routine episiotomy n = 223 | Selective episiotomy n = 222 | RR (95% CI) | P value | |
|---|---|---|---|---|
| First-degree laceration | n/a | 30(13.5) | n/a | n/a |
| Second-degree laceration | n/a | 33(14.9) | n/a | n/a |
| Third- or fourth-degree laceration | 32(14.4) | 15(6.8) | 2.12(1.18-3.81) | .007 |
| Third-degree laceration | 22(9.9) | 10(4.5) | 2.19(1.06-4.52) | .03 |
| Fourth-degree laceration | 10(4.5) | 5(2.3) | 1.99(0.69-5.7) | .192 |
| Periurethral laceration | 6(2.7) | 25(11.3) | 0.24(0.10-0.57) | <.001 |
| Labia minora laceration | 6(2.7) | 21(9.5) | 0.28(0.12-0.69) | .03 |
| Superficial vaginal laceration | 5(2.2) | 23(10.4) | 0.22(0.08-0.56) | .001 |
| Deep vaginal laceration | 6(2.7) | 7(3.2) | 0.85(0.29-2.5) | .77 |
Of the third- and fourth-degree lacerations seen in the selective episiotomy group, 86.6% (13/15) occurred in women in whom episiotomy was performed. Of the 168 women who did not undergo the procedure in the selective episiotomy group, only 2 (1.19%) patients had third- or fourth-degree lacerations.
Fifty-four patients (24.3%) in the selective episiotomy group underwent the procedure. The main reason to perform the procedure was: impending laceration 46 patients (85.2%), fetal distress 4 patients (7.4%), forceps delivery 3 patients (5.5%), other reasons 1 patient (1.7%).
Periurethral, labial minor, and superficial vaginal lacerations were all significantly more frequent in the selective compared to routine episiotomy group (Table 2).
Comment
The use of routine episiotomy in nulliparous women is still commonly seen in our Colombian hospitals, with a frequency ranging between 51-61%. This high frequency may be explained by the fact that many patients and their treating doctors are still convinced of the benefits derived from the performing of such technique.
The purpose of this study was to develop the hypothesis that selective episiotomy has a decreasing effect on the occurrence of third- or fourth-degree perineal lacerations. We found that routine episiotomy was associated with twice as many severe perineal lacerations compared to the selective episiotomy. This difference cannot be attributed to any of the variables involved such as fetal weight, gestational age, or head circumference given the similarity between the 2 study groups. Supporting this risk of episiotomy, the majority of the third- and fourth-degree tears in the selective group were in those women who received an episiotomy. Consistent with the literature, the presence of other minor perineal lacerations such as labia major and minor, superficial vaginal, and periurethral lacerations was significantly higher in the selective episiotomy group.1, 2, 3, 4, 7 The main recommendation based on recent reviews is to not perform routine episiotomy because it favors the occurrence of severe posterior perineal lacerations and their associated morbidity.11, 12 However, the results cannot be extrapolated to a setting where the midline episiotomy prevails because the majority of reviewed trials used mediolateral episiotomy. In retrospective studies midline episiotomy is associated with a risk of deep perineal damage, an additional argument to emphasize the relevance of our results.13, 14, 15, 16, 17
Even though the process of patient allocation within different groups was done by computer, blinding was not performed. However, different attending physicians with no connection to the research group were in charge of the clinical care of the patients and the group in which the patient was allocated was known only during the second stage of labor. However, the attending physicians doing the classification of the degree of perineal laceration had no connection with the research group, as stated before; the implemented strategy to decrease the potential bias on this matter was to include the evaluation of the perineal laceration by the resident who was then required to be in agreement with the attending physician.
The study included patients with preterm delivery because in our city the episiotomy is recommended also in those cases, with the purpose to decrease the chance of fetal trauma. Our protocol accepted pregnant patients with more than 28 weeks of gestation; however, we did not have cases presenting with less than 30 weeks. Our study is the first randomized clinical trial in the world comparing the routine use of midline episiotomy vs the use of selective midline episiotomy in nulliparous patients in the prevention of third- and fourth-degree lacerations. We recommend performing selective episiotomy in all birth centers when caring for nulliparous women.
Acknowledgments
We thank the Hospital San Vicente de Paul of Medellín.
References
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- . Benefits and risk of episiotomy: a review of the English-language literature since 1980 (Part I). Obstet Gynecol Survey. 1995;50:806–820
- . Benefits and risk of episiotomy: a review of the English-language literature since 1980 (Part II). Obstet Gynecol Survey. 1995;50:820–835
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- . Anal incontinence after anal sphincter disruption: a 30 year retrospective cohort study. Obstet Gynecol. 1997;89:896–901
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- . Incontinence following rupture of the anal sphincter during delivery. Obstet Gynecol. 1993;82:527–531
- . Epidural anesthesia, episiotomy and obstetric laceration. Obstet Gynecol. 1991;77:668–671
- . Routine vs selective episiotomy: a randomized controlled trial. Lancet. 1993;342:1517–1518
- . Episiotomy for vaginal birth. Cochrane Database Syst Rev. 2005;CD000081
- . Outcomes of routine episiotomy: a systematic Review. JAMA. 2005;293:2141–2148
- . Midline episiotomy and anal incontinence: retrospective cohort study. BMJ. 2000;320:86–90
- . Midline episiotomies: more harm than good?. Obstet Gynecol. 1990;75:765–770
- . Factors associated with rectal injury in spontaneous deliveries. Obstet Gynecol. 1989;73:732–738
- . Effect of episiotomy on the frequency of vaginal outlet laceracions. J Reprod Med. 1986;31:240–244
- . A comparison between midline and mediolateral episiotomies. BJOG. 1980;87:408–412
Cite this article as: Rodriguez A, Arenas EA, Osorio AL, et al. Selective vs routine midline episiotomy for the prevention of third- or fourth-degree lacerations in nulliparous women. Am J Obstet Gynecol 2008;198:285.e1-285.e4.
PII: S0002-9378(07)02114-X
doi:10.1016/j.ajog.2007.11.007
© 2008 Mosby, Inc. All rights reserved.
Volume 198, Issue 3 , Pages 285.e1-285.e4, March 2008
