Why do you have cystitis after having sex?

Cystitis is a very common pathology among women, especially what is called "bacterial cystitis", caused by infection by bacteria. According to international studies, 60% of women will suffer cystitis at some time in their life; and within that group, up to 80% could be identified as cystitis after having sex.

What is cystitis?

Strictly speaking, the word defines an inflammation of the urinary bladder, whatever the cause. In general, it is assumed that cystitis is the same as a urinary infection, although this is not the case; while cystitis is an inflammation, the urinary infection involves the participation of a microorganism, usually a bacterium.

So we can classify this pathology into two large groups:

  • Infectious cystitis
  • Non-infectious cystitis

Infectious cystitis is caused by a microorganism, in most cases a bacterium, and regularly the bacteria known as Escherichia coli. The microorganism enters the urinary tract, ascending through the urethra and multiplies forming bacterial colonies, which will cause the symptoms of the disease.

Most cases of cystitis are caused by the excessive proliferation of bacteria such as E. Coli. However, this disease can appear due to non-infectious causes.

On the other hand, as non-infectious cystitis we can name those that are caused by:

  • Strange bodies: for using a urinary catheter or a catheter inserted in the urethra.
  • Medicines: The use of chemotherapy for treatments against various cancers has an adverse effect on the inflammation of the bladder.
  • Chemicals: by allergy to certain substances present in feminine hygiene products, such as vaginal foams.
  • Radiation: caused by radiotherapy in women with oncological treatments.
  • Interstitial cystitis: It is an inflammation of the bladder without a valid explanation, which is why it is also difficult to treat.
  • Other pathologies: some diseases affect the bladder, inflaming it, such as the spinal cord conditions that cause the picture known as "neurogenic bladder."

Cystitis after having sex

It is scientifically proven that sexual relations are a risk factor for contracting cystitis among women. According to one study, cystitis is more likely for women who have sex more than four times a month, for those who use contraception and for those who have had sex in the last thirty days.

There is a specific expression for this urinary infection linked sexual intercourse: postcoital cystitis. And at least five reasons were also identified as to why the practice of sex favors urinary tract infection in women:

Oral contraceptives

Women who use hormonal contraceptives by mouth are modifying the menstrual cycle. They also modify the natural actions of the hormones on the female body. Oral hormonal contraceptives weaken the bladder mucosa, that is, the innermost part of the organ, facilitating the colonization of bacteria as Escherichia coli.

Women who take oral contraceptives have a higher risk of cystitis. This type of medicine weakens the mucosa that protects the bladder.


The material of condoms, both male and female, It can also alter the mucosa of the woman's urinary tract, weakening the power of defense, and favoring the rise of bacteria. This will depend a lot on each human being, since not all bodies react in the same way to these materials.

Read also: How to recognize, prevent and treat naturally the urinary infection or cystitis

Bacteria entry

The sex favors the colonization of bacteria from the external environment to the interior of the woman's urinary tract. It can be the same penis that acts as a transporter, or it can be the mechanics and movements of the sexual act.

Coital hygiene

One of the factors most linked to cystitis and sexual relations is the hygiene of the woman at the end of the sexual relationship. When you do not urinate immediately after sex, Bacteria that entered are more likely to remain in the bladder and reproduce.

Small urethral traumatisms

Sex is a traumatism in the urethra of women, which is short-path and is anatomically very close to the vagina. The repetitive movement of the sexual act weakens the female urinary tract favoring the entry of external bacteria by reducing the defense power of the urethra.

Discover: What is interstitial cystitis and how can we treat it?

Prevention of postcoital cystitis

Although it is clear that sexual relations are an important factor for the development of cystitis among women, this does not mean that we should be afraid. Neither is it necessary to suspend sexual practice or avoid it for fear of a urinary infection. Taking enough precautions, and that are easy to apply, the risk of cystitis is markedly reduced.

Consuming water ensures optimal hydration and decreases the risk of cystitis. However, the daily amount of liquid may vary in each person.

The council par excellence to prevent cystitis linked to sexual intercourse is Empty the bladder immediately after the sexual act. This simple action drags bacteria that could have just entered the urethra and bladder.

Since it pushes them outward, it prevents them from beginning their process of colonization within the urinary system. If possible, emptying the bladder before sexual intercourse also increases the defense mechanisms of the body.

This simple advice should be combined, during the rest of the day, with good hydration. Adequate intake of water stimulates the production of urine and facilitates urination during the day. This way, delays and retentions that also favor the appearance of cystitis are avoided.