Monocentric Prospectiv Observational Clinical Trial of Pelvic Floor Biometry During Pregnancy and Puerperium

Pregnancy, childbirth and the puerperium determine significant changes in the muscular, fascial and support structures of the pelvic floor. These changes, both physiological (i.e. dictated by the adaptations that pregnancy determines at the level of the connective tissue, collagen and pelvic-perineal muscular structures) and the changes induced by the passage of the fetus through the birth canal (obstetric lacerations, episiotomy and muscle avulsions) cause a weakening of the pelvic support structures with the possible onset of dysfunctional symptoms, which are not only common in old age, but become evident already in childbearing age. Previous studies on the composition of connective tissue show significant changes in the collagen component both in continent women and in those who experience stress urinary incontinence. These changes are revealed in approximately 24% of the population that suffers from urinary incontinence. Collagen is the main component of the endopelvic fascia. During pregnancy, the hormonal influence typical of this phase determines significant changes in the mechanical properties of the connective tissue and muscle fibers of the levator ani, which tend to hypertrophy and lengthen. This may also explain why cesarean delivery, elective or after the onset of labor, is not fully protective against the development of pelvic floor dysfunction. However, pelvic floor changes may have occurred before delivery and may not necessarily be related to labor and delivery itself. Incontinence, mostly temporary in pregnancy, must be interpreted as the result of these factors in addition to the increased pressure on the urethrovesical junction caused by the gravid uterus. Stretching of connective tissues beyond their physiological limits during labor, resulting in levator ani injury and/or possible neurogenic stretch damage, occurs in the majority of women who give birth vaginally, but in most women, muscle hypertrophy and nerve fiber adaptation compensate for this pathological pattern. In a minority (5-20%) of women, major levator ani defects and neurogenic lesion may lead to irreversible changes in pelvic floor function. Pelvic floor imaging after pregnancy has improved the understanding of the etiology of pelvic floor disorders in animal models. Patients who already present with pelvic static dysfunction and urinary incontinence during pregnancy tend to develop the same problems in the puerperium. However, to date it is not known what moment in pregnancy these changes in the pelvic tissue begin and that cause the progressive change in the myo-connective components of pregnancy. The lack of prospective cohort studies of pregnant and postpartum subjects does not allow a conclusive opinion on this topic. Pelvic floor ultrasound performed transpeineally, useful for evaluating pelvic biometry, is a non-invasive method and well tolerated by the patient, not only in postpartum but also during pregnancy. A previous study examined pelvic floor changes during pregnancy, reporting how the progression of pregnancy determines changes in the anatomical components of the pelvic floor, without however correlating the data with the puerperium and the longer-term outcomes of these changes. We did not identify any previously published studies that attempted to comprehensively assess biometric changes of the pelvic floor during pregnancy and postpartum using not only ultrasound imaging, but also clinical assessment and validated urinary symptom questionnaires.