Pelvic floor disorders are caused by weakening or damage to the tissues lining the bottom of the abdominal cavity. These disorders affect nearly 1 in every 4 women in the United States and symptoms that drastically diminish a patient's quality of life. Vaginal closure force is a good measure of pelvic health, but current vaginal dynamometers were not designed for the rigors of hospital reprocessing, often failing due to sensor degradation through repeated sterilization processes. In order to obtain measurements of vaginal closure force in a large study, we designed a vaginal dynamometer that utilizes a removable intra-abdominal sensor already in production for the study. The sensor's existing data acquisition system was modified to transmit to a tablet allowing the user to view data in real-time. The new speculum design allowed a single sensor to measure vaginal closure force before being used to collect intra-abdominal pressure data in the same study visit. The measurements taken with the new speculum were similar to measurements taken with a previously reported vaginal dynamometer.

Intra-abdominal pressure may be one of the few modifiable risk factors associated with developing a pelvic floor disorder. With one in eight women having surgery to correct a pelvic floor disorder in their lifetimes, intra-abdominal pressure may be a key to understanding the disease etiology and how to mitigate its occurrence and progression. Many traditional methods of intra-abdominal pressure measurement have limitations in data quality, environment of use, and patient comfort. We have modified a previously reported intravaginal pressure transducer that has been shown to overcome other intra-abdominal pressure measurement technique limitations (Coleman 2012). Our modifications to the intravaginal pressure transducer make it easier to use, less costly, and more reliable than previous designs, while maintaining accuracy, integrity, and quality of data. This device has been used in over 400 participants to date as part of one of the most comprehensive studies examining the relationship between intra-abdominal pressure and pelvic floor disorders.

Other than measures of body habitus and lifting duration, we did not identify modifiable factors that could mitigate maximal pressures experienced by the pelvic floor during the early postpartum period.

Objective This study aimed to determine whether measures of muscular fitness modify the effect of intra-abdominal pressure (IAP) during lifting on pelvic floor support. Methods Participants, primiparous women 1 year after vaginal delivery, underwent the Pelvic Organ Prolapse Quantification examination, measurement of IAP via a vaginal sensor while lifting a weighted car seat, pelvic floor muscle force assessment using an instrumented speculum, grip strength using a hand dynamometer, and trunk flexor endurance by holding an isometric contraction while maintaining a 60-degree angle to the table. We dichotomized pelvic floor support as worse (greatest descent of the anterior, posterior, or apical vagina during maximal strain at or below the hymen) versus better (all points above the hymen). Results Of 825 participants eligible after delivery, 593 (71.9%) completed a 1-year study visit. Mean (SD) age was 29.6 (5.0) years. One year postpartum, 55 (9.3%) demonstrated worse support. There were no differences in IAP during lifting or in other measures of pelvic floor loading between women with better and worse support. In multivariable analyses, neither grip strength nor pelvic floor muscle force modified the effect of IAP on support. In women with trunk flexor endurance duration ≥13 minutes, the odds of worse support increased significantly as IAP increased. No fitness measure modified the effect of other measures of pelvic floor loading on support. Conclusions Primiparous women with higher IAP during lifting and greater muscular fitness did not have reduced odds of worse pelvic floor support compared with those with lower IAP at the same muscular fitness.

Objective To determine whether 2 aspects of trunk recovery after childbirth, intraabdominal pressure (IAP) generation and trunk flexor endurance (TFE), predict measures of pelvic floor health 1 year postpartum. Methods In this prospective cohort study, we enrolled nulliparas in their third trimester and followed up those delivered vaginally for 1 year. We measured IAP while lifting a weighted car seat (IAPLIFT), IAP during TFE testing (IAPTFE), and TFE duration 5 to 10 weeks postpartum and assessed pelvic floor support and symptoms 1 year postpartum. Results Mean age of the 624 participants was 28.7 years. At 5 to 10 weeks postpartum, mean (SD) maximal IAPLIFT and IAPTFE were 47.67 (11.13) and 51.57 (12.34) cm H2O, respectively. Median TFE duration was 126 seconds (Interquartile range, 74–211). At 1 year postpartum, 9.3% demonstrated worse support (maximal vaginal descent at or below hymen) and 54% met criteria for symptom burden (bothersome symptoms in ≥2 domains of Epidemiology of Prolapse and Incontinence Questionnaire). In multivariable models, neither IAPLIFT nor IAPTFE were associated with worse support or symptom burden (P = 0.54–1.00). Trunk flexor endurance duration increased prevalence of worse support (prevalence ratio, 1.05; 95% confidence interval, 1.01–1.08) per 60-second increase, P = 0.005) but not symptom burden (prevalence ratio, 1.00; 95% confidence interval, 0.98–1.03; P = 0.92). Conclusions These results provide some reassurance to early postpartum women, who are unlikely to perform routine activities that generate IAP far outside the range tested. Further research is needed to understand why women with long TFE durations have increased prevalence of worse support.