Bleeding as a warning sign: could it be an STI?

Bleeding in the genital area outside of the normal menstrual cycle is concerning for many women. Often, causes such as hormonal fluctuations, irritation of the mucous membranes, or stress are responsible. However, sexually transmitted infections (STIs) like chlamydia or gonorrhea can also be behind it. Men can also experience bleeding, for example from the urethra, which may indicate injuries or infections. This article explains which STIs can cause bleeding, how to distinguish them from other causes, and what actions are recommended.

Table of contents

• What is an STI?
• Can bleeding be a sign of an STI?
• Which STIs are commonly associated with bleeding?
• Other causes of bleeding in the genital area
• Symptoms: When should you be concerned?
• What should I do if I have bleeding and other symptoms?
• How can I protect myself from an STI?
• Summary

What is an STI?

A sexually transmitted infection (STI) is an infection that is primarily transmitted through unprotected sexual contact. It includes infections such as chlamydia, gonorrhea, syphilis, HPV, herpes, or HIV. STIs can be bacterial, viral, parasitic, or fungal in origin and can cause both acute symptoms and long-term complications such as infertility, chronic pain, pelvic inflammatory disease, or an increased risk of HIV infection. To prevent serious consequences, signs of an STI must be recognized and treated early (Cleveland Clinic, 2023).

Can bleeding be a sign of an STI?

Yes, bleeding can be a sign of a sexually transmitted infection (STI). Many STI pathogens cause inflammation of mucous membranes or tissues, making them more sensitive and prone to bleeding.

Which STIs are commonly associated with bleeding?

• Chlamydia and gonorrhea: These are two common bacterial infections that are sexually transmitted and affect the mucous membranes of the genitals, urethra, or rectum. Both can cause inflammation, such as cervicitis (inflammation of the cervix), which may lead to bleeding due to irritation or damage to delicate blood vessels. If left untreated, they can lead to serious complications.
• Trichomoniasis: This parasitic infection irritates the vaginal mucosa, which can lead to small injuries. Irritated tissue bleeds more easily, especially after sexual intercourse.
• Syphilis: In later stages of this STI, painless ulcers (sores) often develop on mucous membranes. These are sensitive and may bleed easily.
• Herpes: Caused by the herpes simplex virus (HSV), this STI leads to blisters and ulcers in the genital or oral area. Bleeding can occur when the blisters rupture or are irritated by friction.

Sources: NHS, 2024; CDC, 2024

Other causes of bleeding in the genital area

Bleeding in the genital area is not necessarily caused by an STI and may have other causes, including:

• Hormonal fluctuations: Changes in hormone levels, such as during puberty, pregnancy, or menopause, can cause unexpected bleeding.
• Injuries: Mechanical irritation or injuries—for example, from rough sexual activity or incorrect use of tampons or sex toys—can lead to bleeding.
• Polyps: Benign growths in the cervix or uterus, often asymptomatic, can occasionally cause spotting or bleeding.
• Fibroids: Benign tumors of the uterus, common in women of reproductive age, may cause heavy or irregular bleeding.
• Endometriosis: A condition where uterine tissue grows outside the uterus, which can cause pain and bleeding unrelated to the menstrual cycle.
• Cancer: Malignant tumors, such as cervical or penile cancer, can cause bleeding, especially in advanced stages.
• Infections: Non-sexually transmitted infections such as bacterial vaginosis or fungal infections can occasionally cause bleeding or irritation.
• Bleeding disorders: Conditions or medications that affect blood clotting can result in mild or severe genital bleeding.

In the case of persistent or unusual genital bleeding—regardless of suspected cause—a doctor should always be consulted to determine the exact reason (MedlinePlus, 2022).

Symptoms: When should you be concerned?

In women, symptoms often appear as spotting, postcoital bleeding (bleeding after sex), or bloody discharge. These symptoms are often caused by inflammation of the uterine or cervical lining. In men, bleeding is less common but can present as blood in the urine, semen, or light bleeding from the urethra. These symptoms may result from urethral infections or mechanical injuries associated with STIs.

Bleeding in the genital area is rarely the only symptom of a sexually transmitted infection (STI). If symptoms do occur—since many STIs can be asymptomatic for a long time—they are often accompanied by the following:

• Unusual discharge from the vagina or penis
• Pain or burning during urination
• Itching or redness in the genital area
• Abdominal pain
• Pain during sexual intercourse
• Rash, blisters, or sores in the genital area

Even without additional symptoms, any unclear bleeding should be evaluated by a doctor to rule out serious conditions (Mayo Clinic, 2023).

What should I do if I have bleeding and other symptoms?

If you notice bleeding along with additional symptoms such as pain, unusual discharge, or burning during urination, you should take the following steps:

• See a doctor: Schedule an appointment with a gynecologist, urologist, or general practitioner to determine the cause.
• Document your symptoms: Record the timing, duration, and intensity of the bleeding as well as any associated symptoms to provide your doctor with detailed information.
• Avoid unprotected sex: Refrain from unprotected sexual activity until the cause is clarified to prevent the potential transmission of infections.
• Get tested: If an STI is suspected, specific diagnostic tests should be performed. In Germany, STI tests are available from general practitioners, gynecologists, urologists, or local health departments. Alternatively, at-home self-tests such as those from Homed-IQ offer a simple and anonymous way to test.

Source: WHO, 2024

How can I protect myself from an STI?

The risk of contracting a sexually transmitted infection (STI) can be reduced through targeted preventive measures. The following steps are especially important:

• Use condoms and dental dams to avoid contact with infectious bodily fluids and minimize the risk of infection.
• Get tested regularly, especially if you have multiple partners or enter new relationships, as many STIs can remain asymptomatic for a long time.
• Maintain open communication about your STI status to promote trust and safety.
• Take advantage of available vaccinations, such as those against HPV and hepatitis B.
• Educate yourself about transmission routes, symptoms, and risks of STIs to make informed decisions—this includes oral sex.

Source: WHO, 2024

Summary

Bleeding in the genital area can be a warning sign of sexually transmitted infections (STIs) such as chlamydia or gonorrhea, especially if accompanied by symptoms like unusual discharge, pain, or burning. In addition to STIs, other possible causes such as hormonal fluctuations, injuries, or cancers should also be medically evaluated. Regular testing, protected sex, and vaccinations—such as against HPV—are important steps to reduce the risk of an STI. Early diagnosis and treatment are essential to prevent serious complications.