The female urethra: urethral function throughout a woman's lifetime.

INTRODUCTION AND HYPOTHESIS: The objective of this narrative review is to describe changes in urethral function that occur during a woman's lifetime. Evaluation of urethral function includes measurements of urethral closure pressure, at rest and during stress, leak point pressure, and the detailed study of anatomical and histological changes of the urethral sphincteric mechanism. METHODS: A literature search in MEDLINE, PubMed, and relevant journals from 1960 until 2020 was performed for articles dealing with urethral function and the impact of aging, pregnancy, and childbirth, female hormones, and menopausal transition on the urethral sphincteric mechanism. Longitudinal and cross-sectional epidemiological surveys, studies on histological changes in urethral anatomy during aging, and urodynamic data obtained at different points in a woman's lifetime, during pregnancy, after childbirth, as well as the effects of female hormones on urethral sphincter function are reviewed. Relevant studies presenting objective data are analyzed and briefly summarized. RESULTS AND CONCLUSIONS: The findings lead one to conclude that a constitutional or genetic predisposition, aging, and senescence are the most prominent etiological factors in the development of urinary incontinence and other pelvic floor disorders. Vaginal childbirth dilates and may damage the compressed pelvic supportive tissues and is invariably associated with a decline in urethral sphincter function. Pregnancy, hormonal alterations, menopausal transition, weight gain, and obesity are at best of secondary influence on the pathology of lower urinary tract dysfunction. The decline of circulating estrogens during menopausal transition may play a role in the transition of fibroblasts to cellular senescence.

A review of the impact of pregnancy and childbirth on pelvic floor function as assessed by objective measurement techniques.

The objective of this narrative review is to study the impact of pregnancy and childbirth on pelvic floor function as assessed by objective measurement techniques with quantitative data carried out during pregnancy and after childbirth. A literature search in MEDLINE and relevant and up-to-date journals from 1960 until April 2017 was performed for articles dealing with the impact of pregnancy and childbirth on pelvic floor function as assessed by objective measurement methods. Only studies describing objective measurement techniques. i.e., urodynamics, ultrasound (US), magnetic resonance imaging (MRI), Pelvic Organ Prolapse Quantification (POP-Q) system, and neurophysiologic tests carried out throughout pregnancy and after childbirth are included. Relevant studies presenting objective quantitative data are analyzed and briefly summarized. The number of studies meeting selection criteria was relatively few. Pregnancy, especially first pregnancy, is associated bladder neck lowering, increased bladder neck mobility, pelvic organ descent, decreased levator ani strength, and decreased urethral resistance. These changes are accentuated after vaginal delivery. Data on the impact of obstetrical and neonatal variables are transient and seem of less importance. Cesarean delivery is not completely protective. In most women, pelvic floor muscle function recovers in the year after delivery. Objective measurement techniques during pregnancy may allow identification of women susceptible to pelvic floor dysfunction later in life and offer the opportunity for counseling and preventive treatment strategies.