Thrombosed external hemorrhoids and anal fissures are common and are responsible for severe discomfort during childbirth. However, the real incidence of these lesions is unknown. The aim of our study was to evaluate their incidence and the risk factors for these lesions during childbirth.
A prospective study with proctologic examination during the last 3 months of pregnancy and after delivery (within 2 months) was performed in 165 consecutive pregnant females.
Fifteen females (9.1 percent) with anal lesions (13 thrombosed external hemorrhoids and 2 anal fissures) were observed during pregnancy. Fifty-eight females (35.2 percent) with anal lesions (33 thrombosed external hemorrhoids and 25 anal fissures) were observed during the postpartum period. Ninety-one percent of thrombosed external hemorrhoids were observed during the first day after delivery, whereas anal fissures were distributed, with no peak, over the two months after delivery. The 2 independent risk factors for anal lesions (among obstetric, baby's, and mother's information) were dyschezia, with a 5.7 odds ratio (95 percent confidence interval, 2.7-12), and late delivery, with a 1.4 odds ratio (95 percent confidence interval, 1.05-1.9). Furthermore, many thrombosed external hemorrhoids were observed after superficial perineal tears and heavier babies (P< 0.05). Only 1 of the 33 patients with thrombosed external hemorrhoids who were observed underwent a cesarean section.
One third of females have thrombosed external hemorrhoids or anal fissures in the postpartum period. The most important risk factor is dyschezia. Traumatic delivery appears to be associated with thrombosed external hemorrhoids.