Prophylactic Antibiotics for Postpartum Perineal Tears

Third-degree perineal lacerations reputedly occur in2.2% to 19% of vaginal deliveries in the UnitedStates.^1,2 Breakdown of a third- or fourth-degreeperineal repair can lead to incontinence of stool or flatus,rectovaginal fistula, or sexual dysfunction.^3,4 Infection atthe operative site occurs in up to 12% of cases,⁵ and a keyfactor in successful anal sphincter repair is the absence ofinfection.⁶

Duggal and colleagues⁷ conducted a prospective, randomized,placebo-controlled study to assess whetherprophylactic antibiotics at the time of third- or fourth-degreeperineal tear repair after vaginal delivery would preventsite-specific wound infection and breakdown. Onehundred forty-seven patients were enrolled. Eighty-threepatients received placebo and 64 received either 1 dose ofa second-generation cephalosporin (1 g of cefotetan orcefoxitin) or 900 mg of intravenous clindamycin. Fortypatients did not return for their 2-week follow-up appointment.The criteria used to diagnose a perinealwound complication were (1) the identification of purulentdischarge and (2) the presence of an abscess at the repairsite.

Analysis of the 107 patients who returned for their2-week follow-up appointment revealed that a perinealwound infection developed in 4 of the 49 patients (8.2%)who received antibiotics and in 14 of the 58 patients (24%)who received placebo. The repair site in 21 patients whomissed their 2-week visit but presented for their 6-weekpostpartum checkup was free of infection. Inclusion ofthese patients altered the overall results slightly such thatinfection developed in 7.3% of women who received antibiotictherapy and in 19.2% of women who receivedplacebo. A significant decrease in the amount of purulentdischarge from the repair site was noted in women whohad received antibiotics compared with women who hadreceived the placebo (4% vs 17%).

The study was well designed and attempted to controlmost variables. The observations were numerically sufficientto demonstrate a trend but not sufficient to documentstatistical significance. Better insight might havebeen attained if observations were given for the 14 patientsin each group with fourth-degree perineal tears.The success of an anal sphincter repair was significantlyinfluenced by the skill of the operating surgeon.

The data could have profited from separating the casesperformed by an attending physician from those performedby a resident. The data also could have profitedfrom subcategorizing outcomes by the type of antibioticused. The absence of bacteriology forces one to presumethat the resultant repair site infections were the consequencesof anaerobic progressions, which-to circumventantibiotic prophylaxis-would have had to have focalhematomas or dead spaces.

Antibiotics appear to exert a beneficial effect in preventingrepair site infections, but equal or greater emphasismust be given to operative site hemostasis. Becausethis was a well-designed, randomized, placebo-controlledstudy of antibiotic prophylaxis for third- andfourth-degree perineal tears, this study is currently thebest data that we have.

References:

• Angioli R, Gómez-Marín O, Cantuaria G, O’sullivan MJ. Severe perineal lacerations during vaginal delivery: the University of Miami experience. Am J Obstet Gynecol. 2000;182:1083-1085.

• Handa VL, Danielsen BH, Gilbert WM. Obstetric anal sphincter lacerations. Obstet Gynecol. 2001;98:225-230.

• Burrows LJ, Cundiff GW, Leffler KS, Witter FR. Predictors of third and fourth degree perineal lacerations. J Pelvic Med Surg. 2004;10:15-17.

• Donnelly V, Fynes M, Campbell D, et al. Obstetric events leading to anal sphincter damage. Obstet Gynecol. 1998;92:955-961.

• Sultan AH, Kamm MA, Hudson CN, Bartram CI. Third degree obstetric and sphincter tears: risk factors and outcome of primary repair. BMJ. 1994;308:887-891.

• Kettle C, Hills RK, Jones P, et al. Continuous versus interrupted perineal repair with standard or rapidly absorbed sutures after spontaneous vaginal birth: a randomized control trial. Lancet. 2002;359:2217-2223.

• Duggal N, Mercado C, Daniels K, et al. Antibiotic prophylaxis for prevention of postpartum perineal wound complications: a randomized controlled trial. Obstet Gynecol. 2008;111:1268-1273.