The area between the vagina and the anus – the perineum – is the most common site for childbirth related injuries. Whereas considerable research- and health care attention has been directed towards consequences and follow-up after obstetric anal sphincter injuries (third- or fourth degree tears), perineal tears not affecting the anal sphincter (second-degree tears) have received less attention. Second-degree tears vary widely in size and thus the extent of damage to the perineal body. Because the integrity of the perineal body is important for normal pelvic floor function, larger second-degree tears may be associated with more morbidity than lesser forms. Therefore, the aim of this study was to assess differences in pelvic floor symptoms in primiparas according to the severity of second-degree perineal tears up to 12 months post-partum.

This was a prospective cohort study with a longitudinal follow-up from mid-pregnancy to one-year post-partum. All women meeting the inclusion criteria were invited to participate whilst attending the hospitals routine ultrasound screening in gestational week 18. The recruitment period was between October 2020 and February 2022. All participants gave birth within July 2022. Inclusion criteria at baseline were having a singleton pregnancy and being able to understand the native language. Exclusion criterion at baseline was female genital mutilation. Ongoing exclusion criteria were: missing response to the baseline questionnaire, delivery in another institution, stillbirth, missing sub-classification of second-degree tears, or third- to fourth-degree tear. In this analysis, data from primiparas with vaginal delivery was used. Pelvic floor symptoms were assessed in pregnancy (at 18 weeks of gestation), at three-, and 12 months post-partum using the self-reported questionnaire “Karolinska Symptoms After Perineal Tear Inventory” (KAPTAIN) (1). This is a psychometrically validated patient-reported outcome measure for symptoms such as a wide/loose vagina, defecation problems, or vaginal flatulence, in women with a history of a perineal tear and a deficient perineum (1). Perineal tears were classified using the classification system recommended by the Royal College of Obstetricians and Gynaecologists. In addition, second-degree tears were subclassified depending on the percentage of damage to the perineal body (2A:<50%, 2B:>50%, 2C: entire perineal body without affecting the anal sphincter) (2). Episiotomies were analysed as a separate group. In our study, all recognized tears were sutured according to national guidelines (3). A linear mixed model was estimated to assess differences between perineal tear categories in trend in pelvic floor symptom scores. The outcome measure was the mean sum scores of the KAPTAIN-inventory at all three timepoints. No power analysis was performed for the outcome of this study.

Four-hundred-and-nine primiparas with vaginal births were included in the analysis. Mean age was 29.9 ± 3.9 years, and the mean pre-pregnancy BMI was 24.5 ± 4.6 kg/m2. The rate of instrumental vaginal deliveries was 19.8% (n=81/409). The mean pelvic floor symptom scores from mid-pregnancy to 12 months post-partum, as estimated by the linear mixed model and subsequent post-hoc analysis, are described in Table 1, and illustrated in Figure 1. There were no significant differences between no tear, first-degree tear, or second-degree tear subcategories in pelvic floor symptom scores over time, or at any specific time-point (Table 1). At three months post-partum, women with episiotomies had significantly higher mean pelvic floor symptom scores compared to those with no- or first-degree tears (mean difference 1.6, 95% CI 0.6-2.6), 2A-tears (mean difference 1.4, 95% CI 0.2-2.7), and 2C-tears (mean difference 1.7, 95% CI 0.0-3.4). Pelvic floor symptoms increased significantly from pregnancy to three months post-partum in all perineal tear categories. For all perineal tear categories except for 2C, pelvic floor symptoms scores decreased significantly from three- to 12 months post-partum. Pelvic floor symptom scores remained higher at 12 months post-partum compared to pregnancy in all perineal tear categories.

Childbirth-related injury to each pelvic floor structure, and the mechanisms behind these injuries, are complex and may affect pelvic floor function. In this prospective longitudinal study, including women already in pregnancy, we found no differences in the assessed pelvic floor symptoms over time or at any time point according to perineal tear category. This suggests that the degree of perineal trauma is not associated with the presence of the assessed pelvic floor symptoms. The lack of reduction to baseline values within 12 months post-partum for women across all perineal tears categories - also in the no- or first-degree category - may imply that vaginal childbirth affects pelvic floor symptoms regardless of the occurrence of perineal tears.

There were no differences in pelvic floor symptoms such as a wide/loose vagina, defecation problems, or vaginal flatulence, according to the severity of second-degree perineal tears.

Rotstein E, von Rosen P, Karlström S, Knutsson JE, Rose N, Forslin E, et al. Development and initial validation of a Swedish inventory to screen for symptoms of deficient perineum in women after vaginal childbirth: 'Karolinska Symptoms After Perineal Tear Inventory'. BMC Pregnancy Childbirth. 2022;22(1):638.
Macedo MD, Ellström Engh M, Siafarikas F. Detailed classification of second-degree perineal tears in the delivery ward: an inter-rater agreement study. Acta Obstetricia et Gynecologica Scandinavica. 2022;101(8):880-8.
Laine K, Spydslaug AE, Baghestan E, Norderval S, Olsen IP, Fodstad K. Veileder i Fødselshjelp: Perinealskade og anal sfinkterskade ved fødsel. Den Norske Legeforening; 2020.

Continence 12S (2024) 101653
DOI: 10.1016/j.cont.2024.101653