Sexually transmitted diseases (STDs) are certain infectious diseases passed from person to person. STDs are usually passed during sexual activity, including vaginal intercourse, anal intercourse and oral sex (mouth-to-genital contact). However, these diseases may be passed during any contact involving the genitals of one person and any bodily tissue of another. A pregnant woman can even pass an STD on to her child during delivery, as well as before or after birth.

Different types of STDs are caused by different organisms. Many STDs are caused by bacteria and viruses, while others are caused by parasites. There are more than 15 types of STDs but some are much more common than others. The most common STDs in the United States include:

• Genital herpes
• Chlamydia
• Gonorrhea
• Syphilis
• HIV/AIDS
• Human papillomavirus

According to the U.S. Centers for Disease Control and Prevention, approximately 19 million STD infections occur in the United States each year. Women, young people and minorities are the groups most often infected with STDs. However, anyone participating in sexual activity is at risk. Certain factors that increase the risk of developing an STD include having multiple sexual partners or having a sexual partner with many partners. People can greatly reduce their risk by using a male latex condom every time they engage in sexual activity. Female condoms may also be used, but they offer less protection.

Common signs and symptoms of an STD include the appearance of a sore or raised bump in the genital area, discharge from the genital area and burning or itchiness in the genital area. In many people, STDs do not cause any signs or symptoms. For this reason, all individuals participating in sexual activity should be tested for STDs. This is especially important for women because lack of symptoms is very common in this population.

Early detection is important because untreated STDs can cause serious complications including liver failure, certain cancers, infertility, neurological problems and death. Infection with STDs can also increase a person’s risk of acquiring the human immunodeficiency virus (HIV). Pregnant women should be tested at their first prenatal visit because STDs can cause serious damage to an infant, including blindness, deafness and mental retardation. In some cases, they may cause death. In addition, most cases of transmission of HIV from mother to fetus can now be prevented with medications, which have greatly reduced the caseload of pediatric HIV cases in the United States.