Urinary incontinence (UI) is a common condition in women that can affect quality of life and lead to significant health costs.1 Pregnancy is one of the major causal factors of UI in women. Urinary incontinence onset often occurs during pregnancy or postpartum with 30–50% women affected.2
Pelvic floor muscle training supervised by a therapist is an effective treatment for UI in women.3–5 It has been demonstrated effective in treating the discomfort associated with postpartum UI.6 Although pelvic floor training has a recognized therapeutic effect, its value in preventing postnatal UI is less well established. Several clinical trials have sought to evaluate whether prenatal pelvic floor training supervised by a physiotherapist had a preventive effect on UI.6 The results of some trials suggest efficacy in late pregnancy and postpartum.7,8 In the majority of these trials, pelvic floor training was supervised by teams specializing in this type of care. We wondered whether it was possible to generalize these results in clinical practice by carrying out a pragmatic multicenter trial in which the women have the choice of therapist like in daily practice. In view of the previous trials, we hypothesized that supervised prenatal pelvic floor exercises would prevent or reduce the severity of postnatal UI compared with written instructions only.
Our primary objective was to evaluate the postpartum effect of written instructions only compared with written instructions with supervised pelvic floor exercises on UI severity 12 months after first delivery.
MATERIALS AND METHODS
Women between 20 and 28 weeks of gestation referred to one of the five participating centers (Nîmes, Poissy-Saint-Germain, Clermont-Ferrand, Clamart, and Saint-Denis-de-la-Réunion) were invited to participate in the study. Inclusion required the women to be nulliparous, at least 18 years of age, covered by health insurance, able to read French, carrying an uncomplicated singleton pregnancy, and without or with UI (including UI before pregnancy). Exclusion criteria were previous delivery or abortion after 22 weeks of gestation, high-risk pregnancy, any condition contraindicating further long-distance travel, or previous pelvic floor muscle training less than 6 months prior. All women gave written consent before participating.
Women were randomly assigned to a group at a 1:1 ratio. Stratification was performed according to the center. The randomized list was generated using the Proc Plan from SAS (block of six). The block sizes were blinded for research and health professionals (information not divulged in the study protocol). The random allocation sequence was secured in sequentially numbered sealed envelopes not accessible to the obstetrician. In each center, the participant allocation was undertaken by a research professional, thus ensuring that the obstetrician was blinded for group allocation.
For the pelvic floor muscle training group supervised by a therapist (hereafter termed “physiotherapy group”), rehabilitation was given by a physiotherapist or midwife chosen by the woman from the list drawn up in each center. Before the start of the study, physiotherapists and midwives practicing perineal rehabilitation in each center were invited to participate in the study and to take part in an initial training course given by a physiotherapist specializing in pelvic floor training (C.R.). The rehabilitation standards required in the study and presented during the training session were as follows. The eight pelvic floor training sessions were to be conducted between the sixth and eighth month of pregnancy at a frequency of one session per week. Each session lasted between 20 and 30 minutes and was performed alone with the therapist present throughout. An evaluation of pelvic floor muscle contraction was performed at each session through vaginal examination.9 Sessions consisted of standing contractions (5 minutes), lying contractions (10 minutes), and learning how to start a pelvic floor contraction just before exerting intraabdominal pressure (knack exercise). Electrostimulation or biofeedback was not used. Women were encouraged to perform daily muscle exercises. There were no specific instructions on the number or intensity of the contractions.
The control group received written information on pelvic floor anatomy and pelvic floor contraction exercises, which were given at the time of inclusion. These instructions were also given to the physiotherapy group.
A self-competed questionnaire was given to patients on the inclusion visit, at the end of pregnancy, and during the visit 2 months postpartum. A final questionnaire was mailed 12 months after childbirth. Clinical examination with a Pelvic Organ Prolapse Questionnaire measurement, clinical assessment of pelvic floor muscle strength (between 0 and 5 according to Laycock),9 and a 24-hour pad test (pad test quantify urine loss by measuring the weight gain of absorbent pads) were performed at baseline and at the 2-month postpartum visit.
Clinical examination was performed by an obstetrician blinded to the groups. No information about the randomized groups was given to staff responsible for prepartum, peripartum, or postpartum care. Women were asked not to reveal their randomized group to caregivers, whether during pregnancy, childbirth, or postpartum care. The International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form questionnaire calculates a score for UI and is validated in French. The International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form score is the primary outcome.10 A pelvic floor symptoms questionnaire (Female Pelvic Floor Questionnaire) validated in French clarifies other urinary and pelvic floor disorders and calculates a score in four areas (bladder, prolapse, bowel, and sex).11 Quality of life was assessed using a specific questionnaire (Contilife)12 and a generic questionnaire (EuroQoL-5D). Voluntary exercises of pelvic floor contractions were measured in both groups through a self-administered questionnaire at the end of pregnancy, at 2 months postpartum, and at 12 months postpartum. Women in the physiotherapy group received an additional questionnaire to verify their participation in prenatal pelvic floor muscle training sessions.
The number of participants to include was based on the International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form score. This score ranges from 0 (no incontinence) to 21 (“all the time” incontinence, with a large amount of losses and maximum discomfort of 10 out of 10); a score between 1 and 5 is considered as slight incontinence.13 The score found in the female population in general is between 1.3 and 2.9 with a standard deviation of 2.4.10,14 Considering that 0 corresponds to no incontinence and 3 is incontinence occurring more than once a week with a small amount of urine and resulting in zero discomfort, we considered a difference of less than 1 point was not clinically significant. To give a (International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form) difference of 1 point 12 months postpartum, 182 patients were needed (standard deviation [SD] 2.4, α=0.05, β=0.20, and bilateral formulation). Based on previous work,15 we estimated the loss of patients to be approximately one third. Therefore, 280 women were invited to take part in the study.
The main analyses focus on the primary (International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form score) and secondary outcomes (UI prevalence, urinary Female Pelvic Floor Questionnaire score, quality-of-life score, pad test, pelvic floor contraction exercises, pelvic floor muscle strength, additional postnatal pelvic floor muscle training, number of postnatal medical visits) and are performed with intention to treat, according to a bilateral formulation and a significance level of 5%, according to what was planned and published.16 In univariate analysis, statistical tests provided for categorical variables were the χ2 test or Fisher's test according to the verification of the conditions of application of the χ2 test and for quantitative variables the Student's t test or Wilcoxon tests according to normality of distributions. The center effect on UI prevalence was analyzed using the Cochran-Mantel-Haenszel test. Statistical analysis was performed using SAS 9.
The study received institutional review board approval by the Comité de Protection des Personnes Sud-Ouest-et-Outre-Mer in September 2007 (#2007-A00641-52). This project was funded by the French Ministry of Health through the Programme Hospitalier de Recherche Clinique in 2007 (project #31-15). The study is registered by the Agence Nationale de Sécurité du Médicament and in ClinicalTrials.gov under number NCT00551551 (http://clinicaltrials.gov/show/NCT00551551).
Of the 282 pregnant women recruited between February 2008 and June 2010, 140 were randomized into the physiotherapy group and 142 into the control group (Fig. 1). The recruitment ended when the required number of patients was reached. The characteristics of women at inclusion did not differ between randomized groups (Table 1); the analysis of the 190 women available for the primary outcome also showed no difference (Appendix 1 available online at https://links.lww.com/AOG/A666). Of the 140 women in the physiotherapy group, 116 completed at least one pelvic floor muscle training session (4–8, median 8) and 97 completed all planned prenatal sessions (Fig. 1). Rehabilitation was supervised by 37 different therapists (physiotherapists and midwives). No adverse effects related to the treatment were reported in the physiotherapy group. The primary outcome was collected from 190 women (67.4%) at 12 months postpartum (93 in the physiotherapy group and 97 in the control group; Fig. 1). Women for whom results could not be collected at 12 months postpartum were younger, less educated, and more often smokers than those who completed the study (Appendix 2 available online at https://links.lww.com/AOG/A666).
The prevalence of UI was 37.6% (100/266) at inclusion to the study (Table 1), 44.2% (99/224) in late pregnancy, 36.0% (76/211) 2 months postpartum, and 35.8% (68/191) at 1 year after birth (Table 2). There were no significant differences in prevalence of UI or severity (International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form score) between groups (physiotherapy compared with control) at the end of pregnancy (odds ratio [OR] 1.0, 95% confidence interval [CI] 0.6–1.7; mean difference −0.2, 95% CI −1.2 to +0.8), at 2 months postpartum (OR 0.8 [0.5–1.4]; mean difference −0.6 [−1.4 to +0.3]), and at the end of the study (OR 0.7 [0.4–1.3]; mean difference −0.2 [−1.2 to +0.7]; Table 2; Fig. 2). We did not find any difference between centers for UI prevalence.
At the end of pregnancy, women in both randomized groups reported a similar frequency and duration of voluntary pelvic floor muscle contraction exercises as well as the number of contractions each time; only six women in the physiotherapy group and 15 in the control group reported doing pelvic floor contraction exercises at home everyday (nonsignificant difference, P=.37).
The blinded clinical evaluation of the value of pelvic floor muscle strength at 2 months postpartum showed no significant differences between randomized groups (Table 2). The matched analysis shows a significant decrease of a quarter point in average muscle strength between inclusion and 2 months postpartum in the control group (−0.25, P=.015, signed rank test), whereas it remained unchanged in the physiotherapy group (+0.08, P=.59, signed rank test), but the difference was not statistically different between the two groups (Table 2).
Secondary analysis based on UI at inclusion showed that among women who reported UI on inclusion, the remission rate was 46.9% in the physiotherapy group and 30.6% in the control group; the difference was not significant (P=.17).
The secondary per-protocol analysis comparing the 116 women who actually carried out their prenatal rehabilitation supervised by a therapist with the 142 women in the control group who received only written instructions found no significant difference in UI severity and in the prevalence of UI at the end of pregnancy (mean International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form score reduction −0.2 [95% CI −1.2 to 0.8]; 44.6 compared with 43.7%; OR 1.0 [95% CI 0.6–1.8]), at 2 months postpartum (−0.6 [−1.4 to 0.3]; 33.7 compared with 38.3%; OR 0.9 [0.5–1.5]), and at 1 year postpartum (−0.2 [−1.2 to 0.7]; 32.3 compared with 39.2%; OR 0.7 [0.4–1.4]).
Prevalence and severity of postpartum UI in primiparous women was not altered by supervised prenatal pelvic floor training compared with those who only received written instructions. This result rejects the hypothesis of a preventive effect of antenatal physiotherapy on the occurrence or exacerbation of UI 1 year after first delivery. Results of the per-protocol analysis also supported this conclusion.
In our trial, the variance in the International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form score was higher than expected (SD 3.5 against 2.4 expected). To show a difference of 1 point with this variance and a power of 80%, twice as many patients would have been required. Insufficient power can make a difference appear as not significant; however, the difference observed on the UI score, −0.2 at 12 months postpartum, was very low and well below the threshold considered to be clinically significant (1 point).
Approximately one third of patients dropped out. The effect of this is probably limited because it was similar in both groups. Furthermore, women who dropped out had similar characteristics at baseline than those who did not drop out. It is therefore unlikely that this would have changed the conclusions of our study.
In France, postpartum pelvic floor muscle training is commonplace (54% of women in the physiotherapy group and 63% in the control group performed postnatal sessions). Postpartum pelvic floor muscle training sessions could mask the effect of the effect of postnatal sessions, but the difference was not significant, thus eliminating this bias.
Women in both groups reported a similar exercise frequency at home. It is possible that as a result of the voluntary nature of this study, women were particularly receptive or conscious to the prevention of UI, which would explain why exercises were carried out in the control group. Six years after the end of the a randomized trial carried out by Glazener et al,17 which focused on postnatal pelvic floor exercises, women in the control group were more likely to continue doing daily contractions that women in the physiotherapy group (12% compared with 6%). Sampselle et al18 showed that written and verbal instructions during pregnancy may have a preventive effect. On the other hand, Bø's19 trial comparing a procedure combining written instructions and fitness classes with a control group showed no difference. In our study, only 5% of women in the physiotherapy group did daily exercises at the end of pregnancy (28% if we count the one participant who reported doing the exercises almost everyday). Adherence to exercises in the physiotherapy group seems low and, in our opinion, partly explains why results are not better in this group.
Strengths of our study include the use of a validated and reliable self-administered questionnaire to assess UI and a long postpartum follow-up. Another strength was the pragmatic design. Women had a choice of therapist, which allowed results to be evaluated as if in general clinical practice. To avoid any bias related to the use of inappropriate pelvic floor training techniques, we took the precaution of standardizing the procedure through preliminary training of therapists by a specialist in the field of pelvic floor training. Furthermore, we used evidence-based practices: intensive exercises supervised by a therapist.20
Our results contradict previous studies that show a preventive effect of supervised pelvic floor training on postpartum UI.7,8,21,22 The Cochrane review is in favor of pelvic floor training during pregnancy.6 However, other studies, including ours and those with the largest number of patients, show negative results (Appendix 3 available online at https://links.lww.com/AOG/A666).23,24 Key differences between our study and previous works is the number of centers and physiotherapists in charge of rehabilitation. The positive earlier trials were single-center and only one to five skilled physical therapists supervised the rehabilitation sessions.7,8,21 The larger number of centers and therapists could induce differences in practices despite our efforts to standardize the procedure and reduce its effect. However, our results show that the preventive effect of antenatal perineal rehabilitation, if it exists, disappears when it becomes widespread outside a specialized center.
Our disappointing results should be compared with those of Hilde and Bø, which did not find a preventive effect for postpartum rehabilitation in a sample comprising women with or without UI (a mixed trial like our study).25 One of the supposed mechanisms of physiotherapy in the treatment of UI is to reinforce pelvic floor muscle strength. However, we do not know whether muscle training has a preventive effect in asymptomatic women. One may wonder through which pathophysiologic mechanism prenatal pelvic floor training could play a preventive role in late postpartum UI. It is, in our opinion, implausible that such a mechanism exists because it assumes that prenatal rehabilitation in the physiotherapy group would be sufficiently effective to avoid obstetric trauma.2,7,26 Our study may suggest that antenatal pelvic floor training prevents postnatal decrease in muscle strength. Our interpretation is that the physiotherapy contributes to muscle reinforcement, but this alone is not sufficient to exert a preventive effect on urinary continence.
Our conclusion is that supervised pelvic floor contraction exercises are not superior to written instructions in preventing postpartum UI in primiparous women.
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