Materials and Methods
This is a 2-armed parallel group RCT evaluating the effect of PFMT on stage of POP, bladder neck position, and POP symptoms in primiparous women, stratified on major levator ani muscle defects. The trial was conducted at Akershus University Hospital, Norway, from February 2010 to May 2012. The study was approved by the Regional Medical Ethics Committee (REK South East 2009/289a), Norwegian Social Science Data Services (2799004), and registered at ClinicalTrials.gov ( NCT01069484 ). All subjects gave written informed consent before entering the study. A primary analysis in this participant population addressing the prevention and treatment of urinary incontinence (UI) has been published. The present study was a planned secondary analysis.
Participants
Women were recruited from a cohort study on pelvic floor dysfunction following first time pregnant women from gestational week 22 until 1 year postpartum and from the maternity ward of Akershus University Hospital, Norway. Inclusion criteria were vaginal delivery to a singleton infant after more than 32 weeks of gestation and ability to understand Scandinavian languages. Instrumental vaginal deliveries were included; 20% (35 of 175) had an instrumental vaginal delivery (33 with vacuum and 2 with forceps). Exclusion criteria included delivery by caesarean section, third, and fourth degree perineal tears and serious illness to mother or child. Women with third and fourth degree tears in Norway are routinely referred to physical therapists for PFMT and could ethically not be allocated to a control group. Intrauterine fetal deaths/stillborns were excluded from the analysis.
Power calculation was done for the primary analyses on UI and was based on the results of a former study. No specific power calculation was done for stage and symptoms of POP. However, based on former prevalence studies, one could assume approximately the same prevalence rates (30%) of POP and UI in the postpartum period.
Kretz Voluson E8 system (GE Health Care AS, Oslo, Norway) with 4-8 MHz curved array 3-dimensional/4-dimensional transperineal ultrasound The women were stratified on major defects of the levator ani muscle assessed with the GE transducer (RAB4-8l/obstetric; GE Health Care AS). At pretest, 6 weeks’ postpartum major defects of the levator ani muscle were diagnosed using tomographic ultrasound imaging of the axial plane at maximal pelvic floor muscle contraction as described by Dietz. The method has shown good intra- and interrater reliability shortly after childbirth.
The participants were randomized in blocks of 10 to either PFMT or control with usual care. The randomization sequence was computer generated and opaque sealed envelopes were used. Allocation of participants into the PFMT and control group was administered outside the assessment room by a project midwife who was not involved in the assessment or the teaching of PFMT to the participating women.
Outcome
Primary outcomes were stage of POP and bladder neck position. Secondary outcome was symptoms of POP (sensation of bulging). Outcomes were measured at 6 weeks (pretest) and 6 months’ (posttest) postpartum.
POP stage
Stage of POP was diagnosed by 1 of 2 gynecologists using the reliable and valid Pelvic Organ Prolapse-Quantification examination (POP-Q) in which the maximal point of vaginal descent is measured relative to the hymen during strain with the woman in the 45-degree lithotomy position. We defined no POP as stages 0 and I and POP as stage II or greater. The POP-Q examination followed a rigorous protocol and a standardized procedure.
Bladder neck position
Two gynecologists performed transperineal ultrasound using the GE Kretz Voluson E8 (GE Healthcare AS) with 4-8 MHz curved array volume (RAB4-81/obstetric). The assessment was done according to Schaer et al in the sagittal plane. Bladder neck level on the Y-axis was used to evaluate position.
Symptoms of POP
Sensation of bulging was assessed by an electronic questionnaire using International Consultation on Incontinence Questionnaire-vag which has demonstrated good reliability, validity, and sensitivity to change. The women answered 2 questions on bulging; whether they perceived bulging inside or outside the vagina.
The gynecologists and physiotherapists assessing POP-Q, bladder neck position, and PFM variables were blinded to symptoms of POP and group allocation.
Ability to contract and PFM strength
Two trained physiotherapists taught and assessed the ability to contract the PFM by observation of the perineum and vaginal palpation. Pelvic floor muscle strength was measured using a high precision pressure transducer connected to a balloon catheter (Camtech AS, Sandvika, Norway). The method has demonstrated good reliability. The middle of the balloon was placed 3.5 cm from the vaginal introitus. Only contractions with simultaneous visible inward movement of the catheter /perineum were considered correct.
Intervention
All women had been recommended in written form at the delivery ward to perform PFMT. At pretest instruction in correct PFM contraction and assessment of PFM function was done before randomization and in the same way for all participants. The PFMT group attended a weekly PFMT class led by trained physiotherapists for 4 months starting at 6-8 weeks’ postpartum. In addition, the intervention group was asked to perform 3 sets of 8-12 close to maximum PFM contractions per day at home. Participants reported adherence to the home program in a training diary, and physiotherapists registered class participation. The control group had no further supervision or follow-up during the intervention period. However, because of ethical reasons they were not discouraged from performing PFMT on their own, but they were asked to follow the prescription for the group they were randomized to.
Statistical analyses
Data were analysed using SPSS, version 15 and Review Manager 5.1 (SPSS, Inc, Armonk, NY). Background variables are reported as numbers and percentages and means with standard deviations (SDs). Data are analysed as intention to treat. For categorical data the last observation was carried forward and for continuous data the baseline value plus the added change observed in the corresponding control group was used. An additional per protocol analysis was performed and based on women adhering to more than 80% of the prescribed training sessions (at home and during group training) who were not pregnant again at the postintervention test at 6 months. Between groups comparisons on nominal data are analysed by χ 2 or Fisher exact test and the Mantel−Haenszel risk ratio (relative risk). Student t test was used to compare differences between groups in change of muscle strength. P value was set to ≤ .05.
Results
One hundred seventy-five primiparous women were randomized into the study. Mean age of the participants was 29.8 years (SD 4.1) and mean body mass index was 25.7 kg/m 2 (SD 4.0). Characteristics of the PFMT and control group are presented in Table 1 . There were no statistical significant differences between groups in gestational age, length of second stage, infant birthweight, head circumference, or numbers with instrumental vaginal deliveries. Two women never met for the group training. Twelve women were lost to follow-up in the PFMT group and 3 in the control group. All were included in the intention to treat analyses ( Figure ).
Description | PFMT (n = 87) | Control (n = 88) |
---|---|---|
Age, y, at delivery | 29.5 (4.3) | 30.1 (4.0) |
Body mass index, kg/m 2 | 26.0 (4.1) | 25.3 (3.9) |
Numbers with major levator ani defects | 27 (31.0%) | 28 (31.8%) |
Numbers with college/university education | 64 (73.6%) | 79 (89.8%) |
Numbers married/cohabitant | 80 (92.0%) | 86 (97.7%) |
Numbers smoking a | 2 (2.4%) | 4 (4.5%) |
Numbers being physically active ≥3 times/wk a | 20 (23.5%) | 29 (33%) |
Numbers doing PFMT >3 times/wk | 26 (30.6%) | 37 (42.0%) |
a Total n =173; missing data on 2 women, both from PFMT (valid percent reported).
Seven of 175 (4%) were not able to contract correctly 6 weeks’ postpartum. Three of these 7 had learned to contract at 6 months’ postpartum (2 from training and 1 from control). Of those participating in the trial 96% of the women in the intervention group adhered to ≥80% of both group and home training sessions. At 6 months’ postpartum 16.5% of the control group reported to have performed PFM exercises ≥3 times per week. There was a statistically significant difference in change of PFM strength from 6 weeks to 6 months in favor of the PFMT group (mean difference −3.6 cm H 2 O; 95% confidence interval, −6.7 to −0.6; P = .02).
No significant differences were found for the primary outcome measures at baseline ( Table 2 : POP stage and Table 3 : details of POP-Q points and bladder neck position). Table 2 shows number of women with POP-Q stage 0, I, or II at baseline 6 weeks’ postpartum and postintervention at 6 months’ postpartum in the PFMT group and the control group. None of the participants had POP stage III or IV. Analyses are reported for the whole group and in the subgroups of women with and without major levator ani muscle defects. There were no statistically significant differences between groups or change in stage of prolapse between groups (data not shown). There was no statistically significant difference between groups in individual POP-Q points or bladder neck position at 6 months’ postpartum ( Table 3 ). Per protocol analyses did not change any of the results.
Description | 6 wks’ postpartum | P value | 6 mos’ postpartum | P value | ||||
---|---|---|---|---|---|---|---|---|
POP-Q stage | 0 | I | II | 0 | I | II | ||
Total study group (n = 175) | ||||||||
PFMT (n = 87) | 21 | 56 | 10 | 26 | 53 | 8 | ||
.66 | .58 | |||||||
C (n = 88) | 24 | 51 | 13 | 24 | 59 | 5 | ||
Stratum with no levator ani muscle defect (n = 120) | ||||||||
PFMT (n = 60) | 17 | 36 | 7 | 20 | 36 | 4 | ||
.95 | .98 | |||||||
C (n = 60) | 18 | 36 | 6 | 19 | 37 | 4 | ||
Stratum with major levator ani muscle defect (n = 55) | ||||||||
PFMT (n = 27) | 4 | 20 | 3 | 6 | 17 | 4 | ||
.26 | .28 | |||||||
C (n = 28) | 6 | 15 | 7 | 5 | 22 | 1 |
Description | 6 wks’ postpartum | 6 mos’ postpartum |
---|---|---|
POP-Q Ap | PFMT: −2.78 (0.4) C: −2.78 (0.5) | PFMT: −2.71 (0.7) C: −2.74 (0.4) |
POP-Q: Bp | PFMT: −2.78 (0.4) C: −2.76 (0.6) | PFMT: −2.79 (0.4) C: −2.75 (0.4) |
POP-Q: Aa | PFMT: −2.21 (0.7) C: −2.12 (0.8) | PFMT: −2.23 (1.1) C: −2.37 (0.9) |
POP-Q: Ba | PFMT: −2.28 (0.6) C: −2.23 (0.8) | PFMT: −2.36 (0.7) C: −2.40 (0.7) |
POP-Q: C | PFMT: −6.52 (1.3) C: −6.14 (1.2) | PFMT: −6.53 (1.3) C: −6.59 (1.2) |
POP-Q: ghD | PFMT: 3.73 (0.8) C: 3.81 (0.8) | PFMT: 3.33 (0.6) C: 3.40 (0.7) |
POP-Q: pb | PFMT: 4.07 (0.7) C: 4.02 (0.7) | PFMT: 3.70 (0.7) C: 3.71 (0.7) |
BN position at rest (Y-axis) | PFMT: 2.63 (0.3) C: 2.64 (0.3) | PFMT: 2.81 (0.3) C: 2.74 (0.4) |