The American Academy of Pediatrics now recommends that teen girls should use birth control methods when they have sex.

The AAP updated its policy on female teens who have sex to include the recommendation that the girls use either hormonal contraceptive implants or intrauterine devices, or IUDs, in addition to condoms, every time they engage in sexual activity. These measures will provide protection against sexually transmitted diseases, or STDs, that other forms of birth control will not offer, says the AAP. The measures also increase the likelihood of preventing pregnancies.

For teens, condoms are the most commonly used form of birth control. However, in the ways that they are typically used, they are the least effective among birth control methods. In contrast, studies suggest that long-acting hormonal implants and IUDs are nearly 100 percent effective in preventing pregnancy and fail less often than oral contraceptives and the skin patch and injected equivalents, according to the Academy.

Hormonal implants and IUDs are more costly because only a medical professional can properly insert them. The methods usually cost hundreds of dollars but are less expensive in the long run, claims Mary Ott, an adolescent medicine specialist and associate professor of pediatrics at Indiana University. Ott is also the AAP policy statement’s lead author.

The AAP supports its recommendation by reasoning that IUDs and implants do not rely on compliance, unlike pills and condoms. IUDs are typically left in place for three to 10 years, and implants last around three years.

Intrauterine devices are small, T-shaped devices that may contain hormones or copper. The IUD is inserted in the cervix and womb to prevent pregnancy. Hormone implants are pregnancy-preventing plastic rods roughly the size of a matchstick that are inserted under the skin of the upper arm.

The AAP policy emphasizes that abstinence is the only pregnancy and STD prevention method that is 100 percent effective.

The updated policy was published in the journal Pediatrics, the official journal of the AAP.