Women using long-acting contraception are 20 times less likely to experience an unintended pregnancy due to contraceptive failure, compared to those using pills, patch or rings, say researchers.
Investigators looked at pregnancy rates for 7,486 women aged between 14-45 years who were given a contraceptive method of their choosing. All participants were sexually active, or planning to become sexually with a male partner during the following six-month period.
The failure rate in the group of people using pills, patch or rings was 9.4%, at three years, and this compared with failure rates of 0.9% in those who had depot medroxyprogesterone acetate (DMPA) injections and 0.7% in the group using IUDs or implants.
Overall, pills, patch or rings conferred a 20-fold risk of unintended pregnancies compared with women using LARCs. Women having DMPA injections were 30% less likely to experience one compared with those using IUDs or implants.
Women under 21 years using a patch, pill or ring had twice the risk of unintended pregnancies compared with older women.
Study lead Dr Brooke Winner, obstetrician at Washington University School of Medicine, USA, said: ‘These data underscore the potential benefits of offering adolescents long-acting reversible contraception to reduce unintended pregnancies in the high-risk age group.’
NEJM 2012; 366: 1998-2007