Answer: Yes.

According to the Guttmacher Institute, up to 57% of unplanned pregnancies are conceived while using a contraceptive. Symptoms of viral STIs can be treated, but they recur and are infectious for life. Men and women who have any STI are up to five times more likely to contract HIV, the virus that causes AIDS.

Most STIs have silent symptoms and therefore go untreated, sometimes leading to:

• Pelvic Inflammatory Disease (PID) in women, which may cause infertility and could cause an Ectopic Pregnancy (a pregnancy growing outside of the uterus)
• Cancer, which can lead to death if undetected

Information on this page provided by the US Centers For Disease Control and Prevention, http://www.cdc.gov/std/default.htm http://www.cdc.gov/nchs/data/series/sr_23/sr23_019.pdf and the Guttmacher Institute http://www.guttmacher.org/pubs/journals/3429402.html