As for the question of urinary tract infections (UTIs), they are common enough after sex that doctors often refer to sexually associated infections as "honeymoon cystitis" ... but are they sexually transmitted diseases?
The term honeymoon cystitis has been around for over 30 years, and it's a compelling one. It refers to the fact that UTIs are quite common in newly married women and in women in the early stages of a sexual relationship. In other words, UTIs occur more frequently in women who are having a lot of sex.
The association between sex and UTIs may be due to any one of a number of factors, including:
- Intercourse, which can push bacteria already in the urethra up into the bladder, where they can cause an infection.
- Bacteria that are normally present in the vagina or on the surface of the vulva moving into the urethra during intercourse.
- Urine getting trapped in the bladder or urethra during sex and providing an opportunity for bacterial growth. Some contraceptive methods, such as diaphragms, put pressure on the urinary tract, increasing the risk of trapping bacteria in the bladder.
- Sexual partners can unknowingly pass bacteria that can cause a UTI, such as E coli.
In other words, although UTIs are associated with sex, they are not necessarily sexually transmitted diseases. In fact, the mechanical act of sexual intercourse probably explains far more of the interaction between sex and UTIs than does the transmission of bacteria during sex. The sexual partners of people with recurrent UTIs do not necessarily experience such infections themselves.
More About UTIs
Urinary tract infections are not a single disease. In some individuals the bladder is the primary site of infection. Other people experience more serious infections that ascend to the kidneys. Furthermore, although honeymoon cystitis is most commonly seen in women, UTIs can occur anywhere along the female or male urinary tract.
A number of factors other than sexual intercourse are also associated with an increased risk of UTIs. These include anatomical factors - such as the length of the urethra - and bathroom hygiene. More controversial associations include a lack of sufficient water consumption and the use of tampons and condoms.
Managing UTI Risk
The most frequent suggestion for reducing the risk of sexually associated urinary tract infections is for people to always urinate after sex. It is thought that peeing after sex may flush any bacteria from the urinary tract. Although there is limited research support for this suggestion, it is unlikely to do any harm.
As for the recommendation that women who experience frequent UTIs drink cranberry juice on a regular basis to acidify their urine and reduce the number of bacteria - that suggestion is also not particularly well supported by current research. Two randomized controlled trials have failed to demonstrate a significant reduction in UTIs for women who regularly drink cranberry juice. However, several in vitro studies have found that cranberry juice may affect the way that bacteria interact with the lining of the urinary tract, so some women may still consider the method worth a try.
That said, women who experience significant, recurrent problems with UTIs should definitely discuss the condition with their doctors. Symptom relief with over-the-counter products is not the same as a cure, and it's possible that what you think is a UTI may actually be a different infection in disguise.
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