Research on development of pelvic floor dysfunction following childbirth is challenging due to symptom latency and its multifactorial etiology [1]. Longitudinal studies are warranted to assess the development over time [2]. Ideally, studies should include women prior to first delivery, since pregnancy and antenatal history of pelvic floor dysfunction are reported as risk factors of pelvic floor dysfunction after delivery [3]. This study provides longitudinal data on pelvic floor symptoms obtained in the first pregnancy and in the proceeding 8 years after first delivery. The aim of our study was to describe the development of urinary incontinence, vaginal and bowel control symptoms from 21 weeks of gestation and up to 8 years after the first delivery stratified by delivery mode.

This is an observational cohort study. Inclusion criteria were nulliparity, singleton pregnancy, and the ability to speak the national language. Exclusion criteria were previous pregnancy of more than 16 weeks of gestation and serious maternal or fetal pathology. Ongoing exclusion criteria were premature delivery before 32 weeks of gestation (at first delivery) and stillbirth (at first delivery). We omitted women from analysis at specific time points if they had an ongoing pregnancy of more than 6 weeks of gestation, and if they had undergone any pelvic floor surgery. The 8-year follow-up was scheduled at least 6 months after the last delivery. The women answered a questionnaire at 21 and 37 weeks of gestation, and at 6 weeks, 6 months, 12 months, and 8 years after the first delivery. The following International Consultation on Incontinence Questionnaire (ICIQ) modules were used: “the urinary incontinence short form”, “the vaginal symptoms module” and “anal incontinence and quality of life module”. We calculated the urinary incontinence sum score, the weighted vaginal symptom sum score, and the bowel control sum score. Demographics and delivery data (at first delivery) were obtained from the women`s electronic hospital records. Information on subsequent delivery modes was obtained at the 8-year follow-up. Study groups were defined according to delivery mode at first delivery: (1) normal vaginal, (2) operative vaginal (vacuum and/or forceps), and (3) cesarean. Information on subsequent deliveries did not re-allocate study participants into a different delivery mode group at the 8-year follow-up. A linear mixed model was estimated to assess the differences between the study groups in trend in scores. A post hoc analysis was performed to estimate mean sum scores in each group at all time points and to assess the between-group differences at each time point. The results of post hoc analyses were illustrated graphically. At the 8-year follow-up, the observed mean sum scores in the cesarean delivery group are plotted for two subgroups: women with exclusively cesarean delivery and women with subsequent vaginal delivery after cesarean delivery.

Of the 300 women included in the study, 193 attended the 8-year follow-up. At first delivery 68.3% (n=200) women had normal vaginal delivery, 24.0% (n=48) had operative vaginal delivery and 15.4% (n=45) had cesarean delivery. Mean time interval from the first delivery to the 8-year follow-up was 8.1 (SD 0.8) years. There was no difference in follow-up time between delivery groups. One woman with normal vaginal delivery at first delivery had undergone pelvic floor surgery and was therefore omitted from the analysis at 8 years. Table 1 shows the demographics and delivery data of the study participants. At the 8-year follow-up, 12 of 30 women had vaginal delivery after their first cesarean delivery. One woman with vaginal delivery had a subsequent operative vaginal delivery. The majority of the study population was multiparous. Twenty-three women had only one vaginal delivery and 7 women had only one cesarean delivery. Figure 1 illustrates estimated mean sum scores at each time point estimated by the linear mixed model stratified by delivery mode. There was a trend towards higher overall scores in women with vaginal delivery compared to women with cesarean delivery throughout the study period. The urinary incontinence and weighted vaginal symptom scores increased during pregnancy in women with vaginal delivery and decreased in women with cesarean delivery. However, differences between delivery groups did not reach statistical significance in the linear mixed model analysis.

The estimated scores in the study population were low compared to the maximum score in each module. Already during pregnancy, the development of the estimated urinary incontinence and weighted vaginal symptom score differed in women with vaginal delivery and women with cesarean delivery. This could suggest an underlying predisposition for pelvic floor symptoms later in life in women who are able to deliver vaginally. The higher estimated bowel control score in the operative vaginal delivery group may be explained by the higher prevalence of sphincter tears in this group. There were no statistically significant differences in estimated scores between study groups, which may be due to the small sample size resulting in wide confidence intervals. The relatively small number of participants in the cesarean delivery group at the 8-year follow-up limited the possibility to perform analysis stratified by women with vaginal delivery after cesarean delivery and women with exclusive cesarean delivery. However, the high observed scores in women with vaginal delivery after cesarean delivery likely influence the cesarean delivery group's estimated score as a whole.

Overall, the estimated scores in the study population were low compared to the maximum score in each module. The development of the scores differed between women with vaginal delivery and cesarean delivery with slightly lower scores in the cesarean delivery group.

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