Effect of dyssynergic defecation during pregnancy on third- and fourth-degree tear during a first vaginal delivery: a case-control study.

Abstract

Determine whether dyssynergic defecation is a risk factor for third- or fourth-degree tear during a first vaginal delivery. A retrospective case-control study was conducted on 549 primiparous women. The case group (n = 140) sustained an anal sphincter tear and the control group (n = 409) had a perineal laceration lower or equal to a second-degree tear. The Knowles-Eccersley-Scott Symptom questionnaire identified women who had dyssynergic defecation. A logistic regression analysis was performed. Anal sphincter tear were 2.94 times higher for women reporting dyssynergic defecation (P = .002; 95% confidence interval [CI], 1.47-5.88). Odds ratios (ORs) were also significant for forceps (P < .001; OR, 6.90; 95% CI, 3.27-14.59), vacuum extraction (P = .009; OR, 2.36; 95% CI, 1.17-4.76), median episiotomy (P = .009; OR, 2.71; 95% CI, 1.54-4.78), and high infant weight (P < .001; OR, 2.25 for each 500 g increase; 95% CI, 1.69-2.99). Dyssynergic defecation seems to increase anal sphincter tear, but prospective studies are needed to confirm the association.