Study design, materials and methods
This study was part of a large interdisciplinary project involving birth-related perineal injuries, endoanal ultrasonography and postpartum pelvic floor disorders. The present study is a follow-up study in the cohort of the aforementioned project. Women who agreed to participate in the study were examined immediately after birth to diagnose perineal injury. The clinical examination consisted of inspection and bidigital palpation in the lithotomy position. Laceration grade was documented according to the International Classification of Diseases Tenth Revision (ICD-10) World Health Organization (WHO) guidelines. (1) Only mediolateral episiotomy was performed. Data on maternal, obstetric and neonatal characteristics were obtained from medical records. Self-reported pelvic floor function data were obtained using a web-based questionnaire. The scored items of the questionnaire were validated. Women with no/first-degree injuries, second-degree injuries, third-/fourth-degree injuries (obstetric anal sphincter injury, OASIS) and cesarean section were compared. Statistical analyses were performed by analysis of variance for continuous data (ANOVA). The chi-square test or Fisher’s exact test was used as needed for categorical data, and the independent-sample t test was used for normally distributed continuous data. Odds ratios were calculated with binary logistic regression analysis, with 95% confidence intervals (CIs). Odds ratios were adjusted for age, body mass index (BMI) and fetal weight when appropriate. Analysis of power was performed in the initial study of the project; because the current study is a follow-up study involving the same cohort, power analysis was not applicable.
The one-year follow-up questionnaire was distributed to 776 women, and 511 participants completed the questionnaire, accounting for a response rate of 66%, 74 (14.2%) were excluded from the analysis of symptoms due to de novo pregnancy, and 12 (2.3%) datasets were illegible/incomplete. There were no differences among the three injury groups regarding maternal age, body mass index, infant head circumference, gestational age at delivery, induction rate, labor augmentation or epidural use. The duration of the active secondary stage of labor was significantly longer in patients with second-degree injuries than in those with an intact perineum or first-degree injuries. There was a significant difference in infant birthweight between patients with no or minor perineal trauma and OASI, with the highest infant birthweight among women affected by OASI. Occiput posterior presentation was more common in the OASI group than in the other groups.
Degree of trauma and odds ratios for symptoms of prolapse, urinary incontinence, anal incontinence, sexual function and other outcomes are presented in Table 1.
Symptoms of prolapse were found in 8.3% of the primiparas one year after delivery. OASI was a risk factor for developing symptoms of prolapse (OR 6.9). In total, 6.2% of patients had to use a finger in the vagina to assist in emptying their bowels.
Urinary stress incontinence was present in 31.0% of women, and 18.0% suffered from urge incontinence. Second degree trauma was a risk factor for stress incontinence (OR 1.6) and giving birth by cesarean section was protective against stress incontinence (OR 0.2) The risk for urge incontinence was elevated in the group with the largest injuries (OR 4.4) An impact on lifestyle was reported by 12.1% of the women with urinary incontinence, and for women with OASI the risk of reporting that they had urinary incontinence that affected their lifestyle was significantly elevated.
Anal incontinence was experienced by 13.9% of women. OASI was a risk factor for anal incontinence (OR 3.1). Severe incontinence with leakage of solid stool was found only after vaginal delivery. The severity of the symptoms seemed more prominent among women in the OASI group, who also had an increased risk of reporting that anal incontinence affected their lifestyle (OR 9.8).
Most of the women were sexually active, although 9.7% of the women had not resumed sexual relations. Dyspareunia was experienced by a large proportion, making up 38.3% of the women who were sexually active. The rate of dyspareunia ranged from 31.3-41.4% in the groups with first/second-degree injuries and cesarean sections and was up to 62.5% in the group with OASI. The risk of experiencing dyspareunia was elevated in women with OASI (OR 2.8) The feeling of being too tight (14.6%) was more common than that of feeling too wide (8.6%).
Perineal pain was experienced by 11.6% of women, and 21 women had mentioned pain that was severe enough to prevent most activities in the last 3 months. This type of severe pain was present in all groups, with elevated risk in the OASI group (OR 4.0) OASI was a risk factor for reporting that that symptoms that originated from their injury still had an impact on daily activity (OR 15). Patients with OASI reported the highest rate of complications.
Interpretation of results
OASIS is an evident risk factor for pelvic floor dysfunction after childbirth, but symptoms of pelvic floor disorder were found to be common, even in women with mild to moderate perineal laceration. Dyspareunia and urinary incontinence were the most common symptoms of pelvic floor dysfunction one year after childbirth. Women who underwent cesarean section generally had a low incidence of dysfunction apart from dyspareunia (31%), for which the prevalence was in line with that in women with an intact perineum. Perineal trauma has been recognized as a risk factor for postpartum sexual heath issues. (2)
An elevated risk for pelvic floor dysfunction associated with a larger injury was observed in our study, and women with OASIS reported a significant impact of their symptoms on daily life. This indicates that strategies should remain focused on preventative measures and improved diagnostics for large perineal lacerations.
Functional impairment is an easy way to identify patients who need further evaluation and treatment. In the aftermath of childbirth-related trauma, early identification of pelvic floor dysfunction enables us to intervene with effective strategies (such as pelvic floor rehabilitation) to prevent subsequent aggravation of pelvic floor dysfunction requiring surgery. Predicting and preventing long-term morbidity due to injury to the pelvic floor will also decrease healthcare cost. (3)
Pelvic floor dysfunction is common one year after childbirth, even in women with moderate injury. Women with OASIS had significantly higher risks of symptoms of prolapse, urge urinary incontinence, pain, dyspareunia and impacts on daily life. Sexual dysfunction was experienced by a large proportion of women one year after giving birth, indicating a further requisite to address women´s sexual health after childbirth.