The CDC offers some helpful guidelines regarding STD testing: HIV testing should occur at least once for anyone between the ages of 13-64 Chlamydia and gonorrhea screenings should be performed at least once each year for sexually active women under 25 years of age, and for older women who have new or multiple partners or other risk factors (including a partner who has been diagnosed with an STD) Pregnant women should be screened for syphilis, hepatitis B, and HIV; at-risk women should also be tested for chlamydia and gonorrhea, with repeat testing throughout pregnancy as needed to protect both the mother and the infant