Antibiotic Prophylaxis Reduces Risk for Postpartum Perineal Wound Complications

Women who received antibiotic prophylaxis had reduced rates of perineal wound complications by the second week after delivery, according to a new study.

Researchers at the Santa Clara Valley Medical Center (San Jose, CA, USA) conducted a prospective, randomized controlled trial that included 147 women who had third- or fourth-degree perineal tears after vaginal delivery. The women were randomized to receive a single intravenous dose of a second-generation cephalosporin (64) or placebo (83) before repair of the perineal tears. Obstetricians and patients were blinded to study drug, and the perineum was examined for evidence of infection or breakdown both at the time of hospital discharge and at two weeks postpartum. Main outcomes were gross disruption or purulent discharge at the site of perineal repair by two weeks postpartum; 40 (27.2%) of the women did not return for their two-week appointment.

The study results showed that perineal wound complications developed in 4 (8.2%) of 49 patients who received antibiotics and 14 (24.1%) of 58 patients who received placebo. At two-week follow-up, there was purulent discharge from the perineal wound in 4% of women who had received antibiotics compared to 17% of those who had received placebo. The groups were similar in parity, incidence of diabetes, operative delivery, and third- versus fourth-degree lacerations. Some of the limitations of the study included early termination because of difficulty achieving desired enrollment number within a reasonable time, patients refusing study participation, and a high no-show rate at two weeks postpartum. The study was published in the June 2008 issue of Obstetrics & Gynecology.

"The anal sphincter is susceptible to trauma during a vaginal delivery. The use of operative vaginal delivery, especially in combination with midline episiotomy, has been associated with a significantly increased risk of anal sphincter trauma in both nulliparous and multiparous women,” concluded lead author Neena Duggal, M.D., and colleagues. "Our high failed-appointment rate and specific patient population may limit the generalizability of our conclusions. We await verification of our findings from future studies, which could also evaluate outcomes in lower-risk populations, as well as longer-term outcomes, such as fecal and flatal incontinence and sexual function and satisfaction.”

During vaginal delivery, complications may include third-degree lacerations extending into the capsule and muscle of the anal sphincter and fourth-degree lacerations extending through the sphincter and into the rectal mucosa. Infection at the repair site may compromise success of an anal sphincter repair, and breakdown of the perineal repair may lead to bowel incontinence, rectovaginal fistula, or sexual dysfunction. Even without clear evidence of perineal wound breakdown or infection, more than one quarter to one half of women report complications three to six months after repair, including incontinence of flatus and incontinence of stools.


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Santa Clara Valley Medical Center