Could I Have an STD and Not Know It?

Medically Reviewed by Arefa Cassoobhoy, MD, MPH on August 11, 2014
From the WebMD Archives

A one-night stand. A summer fling. A new love interest asks about your sexual history. A long-term partner confesses to cheating on you. Any of these could make you wonder, "Do I have an STD?"

So you check below the belt. No itching. No sores. No weird oozing or funky smells. It doesn't hurt when you pee. There's nothing obvious that would send you to the doctor. That means you're OK, right?

Not exactly. It's possible to have an STD and not know it. Sometimes symptoms are mild. Sometimes they can be mistaken for other conditions, like when women have discharge from a yeast infection. Sometimes STDs don't have symptoms at all. Yet they can cause health problems.

Talk to Your Doctor

"The same way we can have germs on our skin, in our mouths, or in our digestive tracts and not know it, we can have germs on or inside our genitals," says Jeffrey D. Klausner, MD. He's a professor of medicine and public health at UCLA's David Geffen School of Medicine. "The only way to learn if you have an STD is to get a checkup and talk to a doctor or nurse about your sexual health."

Women usually discuss sexual health with their gynecologists. But both women and men can speak to their regular doctors or nurse practitioners.

"You don't need to see a specialist. All primary care providers can offer STD tests," Klausner says.

Why You Need to Know

STDs are common. There are about 20 million new cases of STDs in the U.S. each year. More than half of adults will have one in their lifetime. If you haven't been tested, you could pass an STD on to someone else. Even though you don't have symptoms, it can be dangerous to your health and the health of your partner.

Some STDs, including chlamydia and gonorrhea, can cause infertility. This is especially true for women. These diseases can cause pelvic inflammatory disease (PID), an infection of the uterus and other reproductive organs. PID can raise a woman's risk for ectopic pregnancy, a pregnancy outside the womb.

Other STDs, such as syphilis and HIV, can be deadly. Left untreated for years, syphilis can also seriously damage your brain, nervous system, and heart.

Certain strains of HPV can cause cervical cancer in women, cancer of the penis in men, and cancer of the anus in both men and women.

When to Get Tested

According to the CDC, how often you should get tested depends on several things:

  • Your age
  • Your gender (Women are tested more often than men because their risk of infertility is higher.)
  • Whether you have more than one sex partner or have a new sex partner
  • If you're pregnant
  • If you're a man who has sex with men
  • If you have unsafe sex (sex without condoms or that exposes you to a partner's blood, semen, or vaginal fluids)
  • If you share injection drug supplies

If you've never been tested but have been sexually active, there's no time like the present.

"You could have been exposed many years ago and still be infected, so you can still transmit it to someone else," says Teresa T. Byrd, MD. She's an assistant professor of obstetrics, gynecology, and reproductive sciences at University of Texas Medical School at Houston.

Some STDs may take a while to show up, Byrd says. "You may have to repeat certain tests at 1 month and 3 months."

STD Testing

Different STDs have different tests. "It is important to discuss the types of sexual activities you have had. That will direct the doctor in which test to use," Klausner says. You may need to give a blood or urine sample, or get swabs from your genital areas or mouth.

"Your doctor should check all potentially exposed sites. If you've had anal sex, your doctor should check your rectum. If you've had oral sex, your doctor should check your throat," he says. "There are also some swab tests you can do yourself."

Never assume that your doctor automatically checks for STDs when you visit. "Just because you are getting a Pap smear [or blood test], that doesn't mean you are getting tested for everything," he says. "You have to ask which test you are getting. If you're worried and you think you need a test, ask for it."

Show Sources


Jeffrey D. Klausner, MD, MPH, professor of medicine and public health, Department of Medicine, Division of Infectious Diseases and the Program in Global Health, University of California Los Angeles.

CDC: "Fact Sheet: Sexually Transmitted Diseases Pose Severe Threat to Women's Health and Fertility," "Fact Sheet: Incidence, Prevalence, and Cost of Sexually Transmitted Infections in the United States," "STD & HIV Screening Recommendations."

U.S. Department of Health & Human Services: "Syphilis Fact Sheet."

National Cancer Institute: "HPV and Cancer."

American Sexual Health Association: "Statistics on Sexually Transmitted Infections," "Getting Tested for STDs/STIs."

Teresa T. Byrd, MD, assistant professor of obstetrics, gynecology and reproductive sciences; assistant residency program director; student clerkship co-director, University of Texas Medical School at Houston.

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