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. (Am J Obstet Gynecol 2003;189:255-60.)


      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to American Journal of Obstetrics & Gynecology
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Sultan AH
        • Kamm MA
        • Hudson CN
        • Bartram CI
        Third degree obstetric anal sphincter tears: risk factors and outcome of primary repair.
        BMJ. 1994; 308: 887-891
        • Pregazzi R
        • Sartore A
        • Bortoli P
        • Grimaldi E
        • Ricci G
        • Guaschino S
        Immediate postpartum perineal examination as a predictor of puerperal pelvic floor dysfunction.
        Obstet Gynecol. 2002; 99: 581-584
        • Sultan AH
        • Kamm MA
        • Hudson CN
        • Thomas JM
        • Bartram CI
        Anal-sphincter disruption during vaginal delivery.
        N Engl J Med. 1993; 329: 1905-1911
        • Donnelly V
        • Fynes M
        • Campbell D
        • Johnson H
        • Oconnell PR
        • Oherlihy C
        Obstetric events leading to anal sphincter damage.
        Obstet Gynecol. 1998; 92: 955-961
        • MacArthur C
        • Glazener CMA
        • Wilson PD
        • Herbison GP
        • Gee H
        • Lang GD
        • et al.
        Obstetric practice and faecal incontinence three months after delivery.
        BJOG. 2001; 108: 678-683
        • Sorensen SM
        • Bondesen H
        • Istre O
        • Vilmann P
        Perineal rupture following vaginal delivery: long-term consequences.
        Acta Obstet Gynecol Scand. 1988; 67: 315-318
        • Haadem K
        • Dahlstrom JA
        • Ling L
        • Ohrlander S
        Anal sphincter function after vaginal delivery rupture.
        Obstet Gynecol. 1987; 70: 53-56
        • Klein MC
        • Gauthier RJ
        • Robbins JM
        • Kaczorowsky J
        • Jorgensen SH
        • Franco E
        Relationship of episiotomy to perineal trauma and morbidity, sexual dysfunction and pelvic floor relaxation.
        Am J Obstet Gynecol. 1994; 171: 591-598
        • Combs A
        • Robertson P
        • Laros R
        Risk factors for third-degree and fourth-degree perineal lacerations in forceps and vacuum deliveries.
        Am J Obstet Gynecol. 1990; 163: 100-104
        • Leeuw JW
        • Struijk PC
        • Vierhout ME
        • Wallenburg HCS
        Risk factors for 3rd degree perineal ruptures during delivery.
        Br J Obstet Gynaecol. 2001; 108: 383-387
        • Jander C
        • Lyrenas S
        Third and fourth degree perineal tears.
        Acta Obstet Gynecol Scand. 2001; 80: 229-234
        • Zetterstrom J
        • Lopez A
        • Anzen B
        • Norman M
        • Holmstrom B
        • Mellgren A
        Anal sphincter tears at vaginal delivery: risk factors and clinical outcome of primary repair.
        Obstet Gynecol. 1999; 94: 21-28
        • Johanson RB
        • Rice C
        • Doyle M
        A randomised prospective study comparing the new vacuum extractor policy with forceps delivery.
        BJOG. 1993; 100: 524-530
        • Argentine Episiotomy Trial Collaborative Group
        Routine vs selective episiotomy: a randomized controlled trial.
        Lancet. 1993; 342: 1517-1518
        • Sleep J
        • Grant A
        • Garcia J
        • Elbourne D
        • Spencer J
        • Chalmers I
        West Berkshire perineal management trial.
        BMJ. 1984; 289: 587-590
        • Signorello LB
        • Harlow BL
        • Chekos AK
        • Repke JT
        Midline episiotomy and anal incontinence: retrospective cohort study.
        BMJ. 2000; 320: 86-90
        • Helwig J
        • Thorp J
        • Bowes W
        Does midline episiotomy increase the risk of third and fourth-degree lacerations in operative vaginal deliveries?.
        Obstet Gynecol. 1993; 82: 276-279
        • Peleg D
        • Kennedy C
        • Merrill D
        • Zlatnik F
        Risk of repetition of a sever perineal laceration.
        Obstet Gynecol. 1999; 93: 1021-1024
        • Green JR
        • Soohoo SL
        Factors associated with rectal injury in spontaneous deliveries.
        Obstet Gynecol. 1989; 73: 732-738
        • Handa VL
        • Danielsen BH
        • Gilbert WM
        Obstetric anal sphincter lacerations.
        Obstet Gynecol. 2001; 98: 225-230
        • Handa VL
        • Harris TA
        • Ostergard DR
        Protecting the pelvic floor: obstetric management to prevent incontinence and pelvic organ prolapse.
        Obstet Gynecol. 1996; 88: 470-478
        • Eason E
        • Labrecque M
        • Wells G
        • Feldman P
        Preventing perineal trauma during childbirth: a systematic review.
        Obstet Gynecol. 2000; 95: 464-471
        • Learman LA
        Regional differences in operative obstetrics: a look to the south.
        Obstet Gynecol. 1998; 92: 514-519