Place: Norges idrettshøgskole
Pelvic floor muscle function in pregnancy and after childbirth and the effect of postpartum pelvic floor muscle training on urinary incontinence in women with and without major defects of the levator ani muscle.
The overall aim was to study pelvic floor muscle function and pelvic floor muscle morphology in nulliparous pregnant women during pregnancy and after childbirth, and further to evaluate the effect of postpartum pelvic floor muscle training in primiparous women with and without injured pelvic floor muscles.
Studies have shown that urinary incontinence is highly prevalent in the female population. Most studies report prevalence numbers within the range 25-45%. The condition may significantly impact the physical, psychological and social well-being, and may present a barrier for physical activity and exercise. This may inhibit women from lifelong participation in regular physical activity, which is important for maintaining health and fitness.
Vaginal delivery is considered as a main risk factor for weakening of the PFM, and imaging studies of primiparous women delivering vaginally have shown that major levator ani muscle defects could appear among 13-36%. However, there seems to be a paucity of prospective studies from pregnancy to after childbirth presenting clinical data on change of vaginal resting pressure, PFM strength and endurance. Likewise, there is a paucity of studies presenting clinical data on these PFM variables in which women with and without major defects of the levator ani muscle after vaginal delivery.
Systematic reviews conclude that PFM training is effective treatment of urinary incontinence. Evidence based guidelines recommend that pregnant women having their first child should be offered supervised PFMT.
Results from studies on the effect of postpartum PFM training aiming at both prevention and treatment of urinary incontinence (mixed prevention and treatment trials) are conflicting. It has been suggested that mixed trials on prevention and treatment might be effective when the intervention is intensive enough.
The study project had two parts, a prospective cohort study and a randomised controlled trial ( RCT). The project was carried out at Akershus University Hospital in cooperation with the Norwegian School of Sport Sciences during the period 2009-20014. All participants gave written informed consent before entering the studies.
The prospective cohort study including nulliparous women at mid-pregnancy had two points of assessment during pregnancy (gestational week 18-22, gestational week 37), and three points of assessment after delivery (6 weeks, 6 months and 12 months). All participants had a learning session in how to contract the PFM correctly at the first clinical visit. The study was approved by the Regional Committees for Medical Research Ethics (REK South East 2009/170) and the Norwegian Social Science Data Services (2799026), and registered at ClinicalTrials.gov (NTC01045135).
In the RCT, we included primiparous women 6 weeks after vaginal delivery. The participants were recruited from the ongoing cohort study or from the maternity ward at Akershus University Hospital or from community health care clinics within the geographical area of the hospital. All participants had received a customary written leaflet from the maternity ward prior to their discharge containing information on PFM training. In addition an initial learning session on correct PFM contraction was given to all participants at their first visit. The participants were stratified on major levator ani muscle defects being present or not, and thereafter randomly allocated to supervised PFM training over 16 weeks or to control receiving no further intervention. The assessors were blinded for group allocation. Baseline was 6 weeks after delivery and post-intervention was 6 months after delivery. Follow-up assessment was performed 12 months after delivery. The study was approved by the Regional Committees for Medical Research Ethics (REK South East 2009/289a) and the Norwegian Social Science Data Services (2799004), and registered at ClinicalTrials.gov (NTC01069484).
Demographic data, background data, sources on PFM training, data on performed training were collected through electronic questionnaires sent out in conjunction with clinical visits. Data on delivery mode and other obstetric data are collected from the hospital’s electronic birth records.
Paper I –II : Based on data from the prospective cohort study including nulliparous pregnant women at mid-pregnancy.
Paper II-IV: Based on data from the randomised controlled trial of 175 primiparous women. 139 of the women were recruited from the ongoing cohort study and 36 were recruited from maternity ward at the hospital or from local community health care clinics.
Paper I: Hilde G, Staer-Jensen J, Ellström EM, Braekken IH, Bø K. Continence and pelvic floor status in nulliparous women at midterm pregnancy. Int Urogynecol J 2012; 23(9):1257-1263.
Cross-sectional results at mid-pregnancy of the 300 nulliparous pregnant women included in a prospective cohort study, showed that had 89% heard about PFMT at mid-pregnancy, 35% of them performed PFM training ≥ once a week, and 15 % ≥ three times per week. Thirty-five percent reported UI, of whom 48 % performed PFMT ≥ once a week. Four percent of the women (12 of 300) were unable to contract the PFM correctly, of whom ten were straining. Continent women had significantly higher PFM strength and endurance than women with UI, mean difference was 6.6 cmH2O for PFM strength (p=0.003) and 41.5 cmH2Osec for endurance (p=0.010). http://www.ncbi.nlm.nih.gov/pubmed/22426877
Paper II: Hilde G, Staer-Jensen J, Siafarikas F, Engh ME, Braekken IH, Bø K. Impact of childbirth and mode of delivery on vaginal resting pressure and on pelvic floor muscle strength and endurance. Am J Obstet Gynecol 2013; 208(1):50.e1-7.
Of the 300 women included in the ongoing cohort study (Paper I), 277 were followed from mid-pregnancy to 6 weeks after delivery. All PFM measurements changed significantly (p<0.001), both in the group with normal vaginal delivery (n=193) and in the group with instrumental assisted vaginal delivery (vacuum/forceps, n=45): Vaginal resting pressure was reduced by 29% and 30%, PFM strength by 54% and 66%, and endurance by 53% and 65%, respectively. In the group of women with emergency caesarean section (n=29), only vaginal resting pressure changed significantly from pregnancy to after childbirth (10% reduction, p=0.003). Urinary continent women at both clinical visits (mid-pregnancy and six weeks after delivery) had significantly higher PFM strength and endurance than incontinent counterparts being incontinent at both points in time (p<0.05).http://www.ncbi.nlm.nih.gov/pubmed/23103345
Paper III: Hilde G, Staer-Jensen J, Siafarikas F, Gjestland K, Ellström EM, Bø K. How well can pelvic floor muscles with major defects contract? A cross-sectional comparative study 6 weeks after delivery using transperineal 3D/4D ultrasound and manometer. BJOG 2013; 120(11):1423-1429.
The cross-sectional study of the 175 primiparous women included to the RCT 6 weeks after vaginal delivery, showed that 4% were unable to contract their PFM correctly. Women with major levator ani muscle defects (n=55) had 47% lower PFM strength and 47% lower endurance when compared with women without major levator ani muscle defects (n=120). Mean difference was 7.5 cmH2O for PFM strength (p <0.001) and 51.2 cmH2Osec for endurance (p<0.001). No difference was found regarding vaginal resting pressure (p=0.670).http://www.ncbi.nlm.nih.gov/pubmed/23834432
Paper IV: Hilde G, Staer-Jensen J, Siafarikas F, Ellström EM, Bø K. Postpartum pelvic floor muscle training and urinary incontinence: a randomized controlled trial. Obstet Gynecol 2013; 122(6):1231-1238.
In the RCT including 175 primiparous women, were 87 randomized to PFM training (27 with and 60 without major levator ani muscle defects) and 88 to control (28 with and 60 without major levator ani muscle defects). The prevalence of urinary incontinence post-intervention (6 months postpartum) was 34.5 % in the training group and 38.6 % in the control group. The relative risk (RR) analysis showed no significant effect of PFM training on urinary incontinence prevalence, RR of 0.89 (95% CI: 0.60 to 1.32). Stratified analysis of women with and without major levator ani muscle defects gave respectively a RR of 0.89 (95% CI: 0.51 to 1.56) and 0.90 (95% CI: 0.53 to 1.52). http://www.ncbi.nlm.nih.gov/pubmed/24201679