Of all the existing systems for birth control, the most effective, according to astudy published in The England Journal of Medicine (NEJM), are intrauterine devices and implants. According to the study, women who use birth control pills, patches or vaginal ring are 20 times more likely to have an unwanted pregnancythan those using longer-acting forms, such as intrauterine devices (IUDs) or implants.
The pill is the most widely used reversible contraceptive method worldwide, but its effectiveness depends on the ability of women to remember to take the pillevery day. Both the pill and the patches or rings are reliable, especially amongyoung women. But, according to the work of the University of Washington (USA),women under 21 who use birth control pills, patch or ring, had a risk ofunplanned pregnancy almost two times greater than the risk of older women.This finding, experts say, suggests that the use of any longer-actingcontraceptives could prevent more unwanted pregnancies.