In a test tube, commonly used spermicides can kill most organisms that cause STDs, especially those causing gonorrhea and chlamydia, but their effectiveness in vaginal use among different populations is not known. Barrier methods and spermicides may offer some protection against cervical cancer. Oral contraceptives provide no protection against lower tract RTIs. They may increase slightly the risk of candidiasis, chlamydia, and genital warts, but only marginally reduce the risk of PID and the severity of tubal inflammation. Long-acting progestins such as injectables and implants may also help prevent PID, but few data are available.
Hormonal methods help protect against uterine and ovarian cancer.
IUDs increase the risk of bacterial vaginosis. IUD users are also about two to five times more likely to develop PID than women not using a contraceptive method. Risks are highest for women who have never had a child, are exposed to STDs, have multiple partners, or have had an IUD inserted during the prior three months. A history of PID is a contraindication to IUD use. Abortion and deliveries performed in the presence of underlying RTIs or with unclean hands or instruments place women at increased risk of infections and sepsis.