There is a growing body of evidence suggesting that sex steroid hormones influence urinary incontinence (UI). Evidence for this include the distribution of estrogen and progesterone receptors throughout the lower urinary tract, the increased risk of UI following menopause and the efficacy of local, vaginal estrogen at managing UI in post-menopausal women with vaginal atrophy. However other observations, suggest a more complex relationship between hormones and continence. For instance, systemic hormone replacement therapy has been consistently associated with increased risks of UI onset and progression in well-designed studies of post-menopausal women. The relationship of local or systemic hormone use and lower urinary tract symptoms (LUTS) in younger, pre-menopausal women is much less well-studied and -understood. A recent large cohort analysis of pre-menopausal, middle-aged women, found that increasing duration of systemic hormonal contraceptive use was associated with increased risk of UI, though findings from the small number of additional studies on this topic are less supportive. The goal of this study is to investigate the relationship between hormonal contraception use (never, past, and current) and prevalence and risk of LUTS in pre-menopausal women using prospective data from the Boston Area Community Health (BACH) Survey.

The BACH Survey (2002-05) used a stratified 2-stage cluster design to randomly sample Boston adults aged 30-79 for participation; 5506 agreed to participate. Follow-up surveys were conducted ∼5 years after baseline (BACH II, 2008). Data were obtained using interviewer and self-administered questionnaires. Lower urinary tract symptoms were assessed using validated questionnaires (the American Urological Association Symptom Index [1], Sandvik Incontinence Severity Scale [2], and Interstitial Cystitis Symptom Index [3]) and items written specifically for BACH.  LUTS assessed included urgency urinary incontinence, stress urinary incontinence, and other urinary incontinence; urgency; daytime urinary frequency; nocturia; urinary hesitancy; intermittency; weak stream; straining to void; feeling of incomplete emptying; dysuria, pelvic pain, urethral pain, bladder pain; and urinary tract infections (UTIs). Female participants were also asked about ever and current contraceptive use, at baseline and follow-up. 

This analysis included all female participants <40 years of age at baseline. LUTS were grouped into the following categories for analysis: urinary incontinence (urgency, stress, and other urinary incontinence), other storage symptoms (urgency, daytime frequency, nocturia), voiding/bladder emptying symptoms (urinary hesitancy, intermittency, weak stream, straining to void, feeling of incomplete emptying), and lower tract pain (dysuria, pelvic pain, urethral pain, bladder pain). Recurrent UTIs were defined as three or more UTIs in the past 12 months. UTIs in the past six months were not assessed. Associations between hormonal contraception and LUTS prevalence were estimated by prevalence ratios (PRs) in the full study population and those between hormonal contraception and LUTS incidence were estimated by relative risks (RRs) in women without LUTS at baseline. Both PRs and RRs were calculated by Poisson regression with robust variance estimation and incorporating BACH Survey sampling weights. Adjusted models included known risk factors for LUTS and other sociodemographic covariates: age, race/ethnicity, vaginal parity, body mass index (BMI), waist circumference, smoking status, and diabetes. The analysis was performed using SAS statistical software.

Of the 764 eligible female participants <40 years of age, 36.6% were Black, 49.9% were vaginally nulliparous, 60.1% had a BMI less than/equal to 29, and 64.9% were never smokers. Twenty percent were current hormonal contraception users, predominantly combined oral contraceptives; 50.3% were past users, and 29.8% were never users. The prevalence of UI, other storage symptoms, voiding symptoms, and lower urinary tract pain was similar between never, past and current hormonal contraception users. In unadjusted and adjusted analyses (Table 1), a significant positive association was observed between current contraceptive use and prevalent recurrent UTIs, with current contraceptive users having 22 times the prevalence of recurrent UTIs compared to never users. No significant differences were found between contraceptive use and risk of LUTS, though the sample size of this incident analysis was considerably smaller than the prevalent analysis.

Recent studies suggest a relationship between systemic hormone therapy and risk of LUTS in post-menopausal women. Few studies exist exploring the relationship between hormone use and LUTS in pre-menopausal women. While these findings do not suggest a relationship between contraceptive use and urinary incontinence, other storage symptoms, and voiding/bladder emptying symptoms, they do support a relationship between current contraceptive use and the presence of recurrent UTIs in women less than 40 years of age. These findings may potentially be explained by differences in sexual activity, by current hormonal contraception use status or possibly the impact of the hormonal contraception on circulating estrogen levels, leading to a relative hypo-estrogenic state.

Findings from this secondary analysis of BACH Survey data suggest that current contraceptive use is strongly associated with the presence of recurrent UTIs in women less than 40 years of age. Additional studies are needed to better understand this relationship and to promote urinary health in pre-menopausal women.

Barry MJ, Fowler Jr FJ, O’Leary MP, et al. The American Urological Association symptom index for benign prostatic hyperplasia. The Journal of urology. 1992;148(5):1549-1557.
Sandvik H, Seim A, Vanvik A, Hunskaar S. A severity index for epidemiological surveys of female urinary incontinence: comparison with 48-hour pad-weighing tests. Neurourology and Urodynamics: Official Journal of the International Continence Society. 2000;19(2):137-145.
O'Leary MP, Sant GR, Fowler Jr FJ, Whitmore KE, Spolarich-Kroll J. The interstitial cystitis symptom index and problem index. Urology. 1997;49(5):58-63.

Continence 12S (2024) 101575
DOI: 10.1016/j.cont.2024.101575