What Diseases Can Occur When Having Unprotected Sex?

Sexually transmitted diseases, or STDs, can threaten your unborn child, your fertility and even your life. You can lower your risk of contracting an STD by using protection, such as condoms or dental dams, every time you have sex. A condom is a latex or plastic sheath worn over the penis during genital or anal sex, or when oral sex is performed on a man. A dental dam is a thin latex square that can be used to provide a barrier during oral sex on a woman. See your doctor immediately if you suspect you have an STD.

Is This an Emergency?

If you are experiencing serious medical symptoms, seek emergency treatment immediately.

Human Immunodeficiency Virus

Human immunodeficiency virus, or HIV, can be spread through contact with semen, vaginal secretions, rectal fluids or blood during sex. Infection leads to acquired immunodeficiency syndrome, or AIDS. The Centers for Disease Control and Prevention says that many people with HIV have no symptoms and can be unaware they are infected 12. There is no cure for HIV or AIDS, but medications can help manage the illness and prolong life. Even if they are on medication, people with HIV can transmit the infection to another.

Human Papilloma Virus

The CDC says that nearly every sexually active person eventually contracts one or more types of human papilloma virus, or HPV. Some types cause:

  • cancers of the cervix
  • vagina
  • vulva
  • penis
  • anus
  • tonsils
  • back of the throat

An HPV vaccine is available and recommended for young people before they become sexually active, as well as for people in their 20s who have never been vaccinated. Most HPV resolves without progressing to warts or cancer, but you have no way of knowing if you will be one of the lucky ones.

Syphilis and Gonorrhea

Syphilis and gonorrhea are bacterial infections. The Merck Manual for Health Care Professionals says the first sign of syphilis is one or more small painless sores, or chancres, at the inoculation site three to four weeks after exposure 34. The sores can go unnoticed and, left untreated, the infection can spread throughout your body and remain for years. Gonorrhea can cause vaginal or penile discharge, pain with urination and testicular pain in men, but up to 20 percent of women have no symptoms. Untreated, more serious infection and infertility can result. Gonorrhea and syphilis are curable with antibiotics.


The bacterial infection chlamydia is the most commonly reported STD in the U.S., according to the Family Practice Notebook 57. Symptoms can include painful urination, bleeding after intercourse and discharge. However, most people have no symptoms. Chlamydia is curable with antibiotics. If left untreated, chlamydia can cause sterility.


Oral and genital herpes are viral diseases. No vaccine exists and they are incurable, although medication can reduce the number and severity of outbreaks. The American College of Obstetricians and Gynecologists says the outbreaks manifest as one or more painful sores at the site of the original infection 6. During oral sex, oral herpes can be spread to the genital area and vice-versa. Herpes can be spread even when there are no visible sores, and can be passed to a newborn at the time of delivery.


Trichomoniasis is caused by a single-celled parasite. Symptoms include a frothy yellowish-green or grayish-green discharge in women with a fishy odor, itching, swelling and painful urination. However, the Family Practice Notebook says most men and up to 44 percent of women have no symptoms 57. Trichomoniasis is curable with antibiotics, but both you and your sexual partner must be treated or you can become reinfected, which is true of most STDs.