Longitudinal changes in pelvic floor muscle strength among parous women

Pelvic floor muscle strength and influencing factors based on vaginal manometry among healthy women at different life stages: A multicentre cross-sectional study

OBJECTIVE

To assess pelvic floor muscle (PFM) strength and influencing factors among healthy women at different life stages.

DESIGN

Multicentre cross-sectional study.

SETTING

Fourteen hospitals in China.

POPULATION

A total of 5040 healthy women allocated to the following groups (with 1680 women per group): premenopausal nulliparous, premenopausal parous and postmenopausal.

METHODS

The PFM strength was evaluated by vaginal manometry. Multivariate logistic regression was used to determine the influencing factors for low PFM strength.

MAIN OUTCOME MEASURES

Maximum voluntary contraction pressure (MVCP).

RESULTS

The median MVCP values were 36, 35 and 35 cmH2 O in premenopausal nulliparous (aged 19-51 years), premenopausal parous (aged 22-61 years), and postmenopausal (aged 40-86 years) women, respectively. In the premenopausal nulliparous group, physical work (odds ratio, OR 2.05) was the risk factor for low PFM strength, which may be related to the chronic increased abdominal pressure caused by physical work. In the premenopausal parous group, the number of vaginal deliveries (OR 1.28) and diabetes (OR 2.70) were risk factors for low PFM strength, whereas sexual intercourse (<2 times per week vs. none, OR 0.55; ≥2 times per week vs. none, OR 0.56) and PFM exercise (OR 0.50) may have protective effects. In the postmenopausal group, the number of vaginal deliveries (OR 1.32) and family history of pelvic organ prolapse (POP) (OR 1.83) were risk factors for low PFM strength.

CONCLUSIONS

Physical work, vaginal delivery, diabetes and a family history of POP are all risk factors for low PFM strength, whereas PFM exercises and sexual life can have a protective effect. The importance of these factors varies at different stages of a woman's life.

A randomized controlled pilot trial to assess the effectiveness of a specially formulated food supplement and pelvic floor muscle training in women with stress-predominant urinary incontinence

BACKGROUND

Pelvic floor muscle training (PFMT) is the first-line treatment approach for stress urinary incontinence. Creatine and leucine have been shown to improve muscle function. Our aim was to assess the effectiveness of a food supplement and PFMT in women with stress-predominant urinary incontinence.

METHODS

Women with stress-predominant urinary incontinence were randomized in 1:1 ratio to receive daily oral supplementation for six weeks with either a food supplement (treatment group) or placebo (control group). Both groups were instructed to perform standardized daily PFMT. The primary outcome was the Urogenital Distress Inventory Short Form (UDI-6) score. Secondary outcomes were the Incontinence Impact Questionnaire (IIQ-7) score, Patient's Global Impression of Severity (PGI-S), and Biomechanical Integrity score (BI-score) measured by Vaginal Tactile Imager. To have a power of 80% and a significance level of 5% to detect a decrease of 16 points in the UDI-6 score, a sample size of 32 was needed, with 16 patients in each arm of our trial.

RESULTS

Sixteen women in the control group and sixteen in the treatment group completed the trial. Between-group analysis revealed no significant differences between the control and treatment group except for mean change (delta) in vaginal squeeze pressure [(cmH2O, mean ± SD), 5 ± 12 vs. 15 ± 15, P = 0.04] and mean change (delta) in PGI-S score [(mean ± SD), -0.2 ± 0.9 vs. -0.8 ± 0.8, P = 0.04]. Within-group analysis showed that UDI-6 and IIQ-7 scores improved significantly from baseline to six weeks in the treatment group but not in the control group [UDI-6 score (mean ± SD) 45 ± 21 vs. 29 ± 21, P = 0.02; 43 ± 18 vs. 33 ± 26, P = 0.22] [IIQ-7 score (mean ± SD) 50 ± 30 vs. 30 ± 21, P = 0.01; 48 ± 23 vs.40 ± 28, P = 0.36]. PGI-S scores only improved in the treatment group from baseline to six weeks after treatment [PGI-S score (mean ± SD) 3.1 ± 0.8 vs. 2.3 ± 0.8, P = 0.0001]. BI-score, on average, improved significantly in the treatment and control group as well [SD unit, mean, from - 1.06 to -0.58, P = 0.001; from - 0.66 to -0.42, P = 0.04].

CONCLUSIONS

Women with stress-predominant urinary incontinence receiving a specially formulated supplement in addition to daily PFMT for six weeks had significantly improved urinary symptoms (decrease in UDI-6 score and IIQ-7) and BI-score compared to their baseline.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05358769. 27/04/2022.

Association between infant birthweight and pelvic floor muscle strength: a population-based cohort study

BACKGROUND

To assess the relationship between infant birthweight and pelvic floor muscle (PFM) strength in China.

METHODS

We performed a retrospective, single-center cohort study of 1575 women delivering vaginally between January 2017 and May 2020. All participants completed pelvic floor examinations within 5-10 weeks after delivery and were evaluated for PFM strength, which was estimated by vaginal pressure. Data were collected from electronic records. We evaluated the association between infant birthweight and vaginal pressure through multivariable-adjusted linear regression analysis. We also performed subgroup analyses stratified by potential confounders.

RESULTS

Vaginal pressure decreased as the quartile of birthweight increased (P for trend < 0.001). Beta coefficients were -5.04 (95%CI -7.98 to -2.1), -5.53 (95%CI -8.5 to -2.57), -6.07 (95%CI -9.08 to -3.07) for birthweight quartile 2-4, respectively (P for trend < 0.001), independent of age, postpartum hemorrhage, and the number of vaginal deliveries. In addition, the results of subgroup analyses showed the same patterns across strata.

CONCLUSIONS

This study demonstrates that infant birthweight was associated with decreased vaginal pressure in women after vaginal delivery and could be considered a risk factor for decreased PFM strength in the population with vaginal delivery. This association may provide an extra basis for appropriate fetal weight control during pregnancy, and for earlier pelvic floor rehabilitation of postpartum women delivering babies with larger birthweight.

Pre-pregnancy body mass index has greater influence on newborn weight and perinatal outcome than weight control during pregnancy in obese women

BACKGROUND

The pre-pregnancy weight and gestational weight gain (GWG) are closely related to perinatal maternal and infant complications, but the relationship between pre-pregnancy weight and GWG and the pattern of interaction have not been reported. This study investigated the influence of weight control during pregnancy on the perinatal maternal and infant outcomes.

METHODS

A total of 835 singleton pregnant women who were hospitalized between January 2018 and December 2018 were retrospectively included in this study and divided into two groups: the diet guidance (DG) group (n = 167) and the control group (n = 668). The pre-pregnancy body mass index (BMI), GWG, and perinatal outcomes of the women and infants were determined in two groups.

RESULTS

The dietary modification and reasonable exercise during pregnancy effectively reduced the GWG, and even some women with pre-pregnancy obesity achieved weight loss during pregnancy. The GWG in the DG group was significantly lower than in the control group, especially in the second and third trimesters. GWG was positively related to birth weight. The birth weight in the DG group was significantly lower than in the control group when their mothers had similar GWG. In women with pre-pregnancy obesity, GWG seemed to be negatively related to birth weight. However, after adjusting the mean BMI, the pre-pregnancy BMI and GWG were positively related to the birth weight. Compared with the control group, the incidences of dystocia, postpartum hemorrhage, macrosomia, small for gestational age infants and neonatal complications significantly reduced in the DG group, and the preterm birth rate was comparable between two groups. Some women with pre-pregnancy obesity lose weight during pregnancy, but there was no premature birth or small for gestational age infant. The incidences of macrosomia, postpartum hemorrhage, dystocia, cesarean section and gestational diabetes increased significantly with the increase of pre-pregnancy BMI.

CONCLUSION

For women with increased pre-pregnancy BMI, strict weight control is required to reduce obesity-related complications of the mother and infant. The weight control in the second and third trimesters is especially important and most likely to prevent GWG. Compared with GWG, pre-pregnancy BMI has greater influence on the birth weight and maternal and infant complications, and may even compromise the benefits of weight control during pregnancy. Thus, weight control is recommended before pregnancy.

Two year follow-up and comparison of pelvic floor muscle electromyography after first vaginal delivery with and without episiotomy and its correlation with urinary incontinence: A prospective cohort study

INTRODUCTION

Few prospective studies have revealed the long-term neuromuscular alterations of pelvic floor after vaginal delivery. The aim of this study was to evaluate the impact of episiotomy on the electrical activity of pelvic floor muscle 2 years following vaginal delivery, and explore the relation between surface electromyography (sEMG) amplitudes and urinary incontinence.

MATERIAL AND METHODS

A total of 427 primiparous women with full-term singleton vaginal delivery were included in the cohort and 362 with no further births within the 2 year follow-up completed observations. Of these, 200 underwent episiotomy and 162 underwent nonepisiotomy. Clinical demographic characteristics, vaginal EMG variables and urinary incontinence-specific questionnaire scores were collected at 6 weeks, 6, 12 and 24 months after childbirth, respectively. Primary outcomes were the comparison of sEMG values between the episiotomy and nonepisiotomy groups throughout 2 years. Secondary outcomes were the correlation between sEMG of both groups and the incidence and severity of urinary incontinence. Spearman's correlation analysis, Kruskal-Wallis test and ANOVA with Bonferroni correction were used to analyze the variables.

RESULTS

Amplitude of maximal fast and endurance contractions on sEMG in the episiotomy group was significantly lower than the nonepisiotomy counterpart. Such difference of sEMG persisted for a long period after birth: endurance contraction, 33.12 ± 8.92 vs 35.085 ± 9.98, p < 0.01 at 24 months, and fast contraction, 36.53 ± 8.87 vs 39.05 ± 9.98, p = 0.01 at 12-month. Although there was no significant difference in incidence and severity of urinary incontinence between both groups, a negative correlation existed between EMG values of muscle contraction and urinary incontinence symptoms throughout.

CONCLUSIONS

Primiparous women delivered with episiotomy demonstrated lower contractile sEMG activity of pelvic floor muscle in the long term. The lower sEMG values of fast contraction were associated with urinary incontinence symptoms.

Randomized controlled trial for improved recovery of the pelvic floor after vaginal delivery with a specially formulated postpartum supplement

Objective

To improve pelvic floor recovery after vaginal delivery with daily supplementation of a specially formulated postpartum recovery supplement.

Methods

Within 48 hours of vaginal delivery, primipara women were randomized in a 1:1 ratio to receive daily oral supplementation for 6 weeks with either a combination of regular prenatal vitamin (PNV), leucine (4 g/day), zinc (30 mg/day) and omega-3 fatty acid (900 mg/day) (treatment group), or only a PNV daily (control group). Co-primary outcomes were vaginal squeeze pressure as measured by perineometer and levator muscle injury as measured by transperineal 3-dimensional tomographic ultrasound at 6 weeks postpartum.

Results

Twenty-six women in the control group and 27 in the treatment group completed the trial. Weak pelvic floor muscle strength was significantly less frequent in the treatment group compared to the control group at 6 weeks after delivery (28% vs. 58%, P=0.03). Both right and left-sided levator-urethra gap was significantly larger in the control group compared to the treatment group indicating more levator injury being present in the control group at 6 weeks after delivery. Anterior vaginal wall prolapse at or beyond the hymenal ring was significantly more common in the control group compared to the treatment group (19% vs. 0%, P=0.02). Significantly more women reported bothersome bulge symptoms in the control group compared to the treatment group at 6 weeks postpartum (19% vs. 0%, P=0.02).

Conclusion

Postpartum women who received a specially formulated postpartum recovery supplement had improved recovery of the pelvic floor after vaginal delivery.

Pelvic organ prolapse as a function of levator ani avulsion, hiatus size, and strength

BACKGROUND

Obstetrical levator ani muscle avulsion is detected after 10%-30% of vaginal deliveries and is associated with pelvic organ prolapse later in life. However, the mechanism by which levator avulsion may contribute to prolapse is unknown.

OBJECTIVES

This study investigated the extent by which size of the levator hiatus and pelvic muscle weakness may explain the association between levator avulsion and pelvic organ prolapse.

STUDY DESIGN

This was a supplementary study of a longitudinal cohort of parous women enrolled 5-10 years after first delivery and assessed annually for prolapse (defined as descent beyond the hymen) for up to 9 annual visits. For this substudy, vaginally parous participants were assessed for levator avulsion using 3-dimensional transperineal ultrasound. Ultrasound was performed at a median interval of 11 years from delivery. Ultrasound volumes also were used to measure levator hiatus area with Valsalva. Pelvic muscle strength was measured with perineometry. Women with and without pelvic organ prolapse were compared for levator avulsion, levator hiatus area, and pelvic muscle strength, using multivariable logistic regression yielding a measure of mediation. Bootstrap methods were used to calculate the confidence interval corresponding to the measure of mediation by hiatus area and pelvic muscle strength.

RESULTS

Prolapse was identified in 109 of 429 (25%) and was significantly associated with levator avulsion (odds ratio, 4.17; 95% confidence interval, 2.28-7.31). Prolapse also was associated with levator hiatus area (odds ratio, 1.52 per 5 cm²; 95% confidence interval, 1.34-1.73) and inversely with muscle strength (odds ratio, 0.87 per 5 cm H₂O; 95% confidence interval, 0.81-0.94). In a multivariable logistic model including levator avulsion, levator hiatus area, and strength, the association between levator avulsion and prolapse was substantially attenuated and indeed was no longer statistically significant (odds ratio, 1.75; 95% confidence interval, 0.91-3.39). Hiatus area and strength mediated 61% (95% confidence interval, 34%-106%) of the association between avulsion and prolapse. Furthermore, since the 95% confidence interval for this estimate contained 100%, it cannot be ruled out that the 2 markers fully mediate the effect of avulsion on prolapse.

CONCLUSIONS

The strong association between pelvic organ prolapse and levator avulsion can be explained to a large extent by a larger levator hiatus and weaker pelvic muscles after levator avulsion.