Progesterone and UTI Risk
Progesterone-only contraceptives, specifically depot-medroxyprogesterone acetate (DMPA), may increase the risk of urinary tract infections in reproductive-age women, particularly those with a history of UTI during pregnancy. 1
Evidence for Progesterone-Associated UTI Risk
The only direct evidence examining progesterone's relationship with UTIs comes from a cohort study of 200 women using DMPA for contraception compared to 200 women using withdrawal method. 1 Key findings include:
- Women using DMPA had significantly higher rates of UTI and urological symptoms compared to controls (p = 0.018 for UTI rate, p < 0.0001 for urological symptoms). 1
- The mechanism involves progesterone's effects on urinary tract physiology: decreased muscle tone, reduced ureteral peristalsis, and alterations in urinary vasculature that may predispose to bacterial colonization. 1
- Among DMPA users who developed UTI, 60% (6/10) had a history of UTI during previous pregnancy, suggesting a vulnerable subpopulation. 1
Clinical Recommendation Algorithm
For women considering DMPA:
- Avoid DMPA in women with a history of UTI during pregnancy, as this population demonstrated the highest risk in the available evidence. 1
- Consider alternative contraceptive methods (non-hormonal IUD, barrier methods, or combined oral contraceptives) for women with recurrent UTI history. 1
For women already using DMPA who develop recurrent UTIs:
- Discontinue DMPA and switch to alternative contraception. 1
- Treat acute UTI with appropriate antibiotics (trimethoprim-sulfamethoxazole 160/800 mg twice daily for 7 days if local E. coli resistance <20%). 2
Important Context: Oral Contraceptives vs. Progesterone-Only Methods
The evidence base distinguishes between different hormonal contraceptive types:
- Oral contraceptives (combined estrogen-progesterone pills) are NOT associated with increased UTI risk. In fact, young women on oral contraceptives with recurrent UTIs may benefit from local vaginal estrogen therapy (1mg estriol 7 times weekly for 2 weeks, then twice weekly for 2 additional weeks), which achieved an infection-free period in 80% (24/30) of patients over 11 months of follow-up. 3
- The UTI risk appears specific to progesterone-only depot formulations (DMPA), not combined hormonal contraceptives. 1
Mechanism and Physiologic Considerations
- Progesterone causes decreased bladder and ureteral smooth muscle tone, reducing the mechanical clearance of bacteria from the urinary tract. 1, 4
- Progesterone alters urinary vasculature, potentially affecting local immune responses and tissue integrity. 1
- These effects are distinct from estrogen's protective role, which maintains vaginal pH, promotes lactobacillus colonization, and improves bladder perfusion. 3, 5
Critical Pitfall to Avoid
Do not extrapolate UTI risk from DMPA to all hormonal contraceptives. Combined oral contraceptives containing estrogen do not carry the same risk and may even be compatible with adjunctive local estrogen therapy for UTI prevention in symptomatic women. 3