Today I’d like to take a closer look at the role of hormones on bladder health. Hormones have been known for a while to play a role in lower urinary tract symptoms such as UTIs, interstitial cystitis and stress incontinence. Hormones may be the reason why women generally seem to be more prone to bladder problems than men and also why some symptoms may get worse at certain times of the month.

The female genital tract and the lower urinary tract are made from the same embryological tissue. Therefore, both are sensitive to the effects of female sex hormones throughout life.

There are receptors (docking stations) for oestrogen and progesterone in the vagina, bladder, urethra and pelvic floor musculature [1].

Oestrogen especially is known to play an important role in the urinary tract, although the role of other hormones have not been defined clearly.

For example, changes in oestrogen levels after menopause have been associated with symptoms such as urinary frequency, nocturia (frequently having to get up at night to go to the toilet), urgency incontinence and recurrent UTIs as well as vaginal symptoms such as dryness, burning and itching [1].

Female Hormones

The two main female hormones are oestrogen and progesterone.

Oestrogen is the main hormone in the first half of the cycle, when the female body is preparing for ovulation and conception.

The second half of the cycle after ovulation and before menstruation is dominated by progesterone, which helps the body start pregnancy in case of conception.

Luteinizing and follicle stimulating hormones are two other important players in this hormonal ‘dance’.

Small amounts of testosterone are also important to help with (sex) drive and muscle integrity.

After menopause, the body produces a lot less oestrogen and testosterone production also tends to decrease.

Oestrogen and Urinary Tract Infections

The incidence of UTIs often seems to rise after menopause. Among other influences, low oestrogen levels may induce structural and chemical changes in the urinary tract that increase the likelihood of catching an UTI [2].

Firstly, oestrogen seems to influence the microbiome. This has been documented in the vagina [3] but has not quite been established for the bladder. However, we now know that the bladder is not sterile but has its own micro flora, so there is reason to believe that this could also be influenced by oestrogen. Oestrogen may help friendly Lactobacilli bacteria to establish themselves in the vagina, helping to protect the bladder from invasion [3].

Oestrogen also influences immune cells and the release of anti-microbial chemicals in the bladder and may therefore play a role in how effectively an infection is warded off [3].

Oestrogen has been found to strengthen urinary tissue by tightening the top layer of cells, which protects the underlying cells from infection [4].

One defence mechanism of the body is to shed cells on top of the bladder tissue in case they have been infected. This may make the underlying cells more susceptible to infection. Oestrogen may help to better connect cells and prevent excessive shedding [4].

On the other hand, higher amounts of oestrogen may make it easier for pathogens to invade bladder cells, which may be the reason why a lot of young women are also highly susceptible to UTIs [4].

Oestrogen and Interstitial Cystitis

Many cases of interstitial cystitis have a high mast cell count. Mast cells in the bladder have been found to have receptors with a high affinity for oestrogen [5].

Mast cells activation (the release of inflammatory chemicals from mast cells) can play a role in IC flares. Interestingly, bladder mast cell activation can be increased by oestrogen [6].

Hormonal manipulation has been shown to improve IC symptoms in at least one study [7].

These findings may explain why IC symptoms often worsen before menstruation [5, 6].

Hormones and Incontinence

Oestrogen plays an important role on the continence mechanism in the bladder. This may be because it helps to raise the sensory threshold in the bladder (i.e. the point at which the bladder has to be voided is higher). It may also increase the resistance of the urethra (bladder opening) and affect the bladder muscle [1].

Recently it has also been shown that testosterone plays and important role in maintaining continence. Testosterone levels also often decline with age.

This may be because testosterone has an anabolic (building) effect on muscles and specifically it helps to maintain pelvic floor muscle strength. Maintaining pelvic floor strength is important for reducing the chance of incontinence [8].

So as we can see, hormones may play an important role in lower urinary tract symptoms and this connection may explain why these symptoms occur more in women and also why some symptoms can fluctuate throughout the cycle.

Now I’d like to hear from you: Have you notice increased bladder issues after hormonal changes? Let me know in the comments!



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Sources

1. Robinson, D. et al The effect of hormones on the lower urinary tract. Menopause Int. 2013 Dec;19(4):155-62 https://www.ncbi.nlm.nih.gov/pubmed/24336244
2. Lüthje, P. Estrogenic action on innate defense mechanisms in the urinary tract. Maturitas. 2014 Jan;77(1):32-6. doi: 10.1016/j.maturitas.2013.10.018. Epub 2013 Nov 5. https://www.ncbi.nlm.nih.gov/pubmed/24296328
3. Silva, C. et al Effects of estrogen administration on the colonization capability of lactobacilli and Escherichia coli in the urinary tracts of mice. Methods Mol Biol. 2004;268:387-399. https://www.ncbi.nlm.nih.gov/pubmed/15156049
4. Bahar Gholipour How Estrogen Fights Urinary Tract Infections Live Science June 19, 2013 https://www.livescience.com/37563-uti-estrogen-menopause.html?utm_source=Twitter&utm_medium=social&utm_campaign=CystitisInfo&utm_content=Menopause
5. Pang et al Bladder mast cell expression of high affinity oestrogen receptors in patients with interstitial cystitis BJUI Volume 75, Issue 2 February 1995 Pages 154–161 http://onlinelibrary.wiley.com/doi/10.1111/j.1464-410X.1995.tb07303.x/full
6. ConstantineSpanos et al Carbachol-induced bladder mast cell activation: Augmentation by estradiol and implications for interstitial cystitis Urology Volume 48, Issue 5, November 1996, Pages 809-816 http://www.sciencedirect.com/science/article/pii/S0090429596002397
7. Lentz GM et al Hormonal manipulation in women with chronic, cyclic irritable bladder symptoms and pelvic pain. Am J Obstet Gynecol. 2002 Jun;186(6):1268-71; discussion 1271-3. https://www.ncbi.nlm.nih.gov/pubmed/12066108
8. Jody A. Charnow Low Testosterone Increases Women’s Urinary Incontinence Risk Renal and Urology News May 14, 2017 http://www.renalandurologynews.com/aua-2017-annual-meeting/low-t-ups-ui-risk-in-women/article/661477/?platform=hootsuite