What is the most effective form of contraception besides abstinence?

Impant or IUD: The two best forms of reversible contraception are the Progesterone implants and the Progesterone or copper intrauterine devices.

LARCs: Long-acting reversible contraception includes intrauterine devices (the Mirena (levonorgestrel) which lasts up to 5 yrs, and may cause lighter or no periods or paragard lasts up to 10 years and has no hormones but may cause heavier/crampier periods) and the nexplanon, the implantable progestin-containing rod that goes under the skin of the upper arm and lasts up to 3 years.Both are> 99% effective to prev.Pregnancy.

IUDs or implants: Iuds or implants have among the lowest pregnancy rates and are more reversible than depot provera (medroxyprogesterone). All of these, however, do not protect at all against stds. For a nice recent study, see: http://www.Nejm.Org/doi/full/10.1056/nejmoa1110855#t=article.

An IUD: If you desire future child-bearing, the iud (intrauterine device) has the highest success rate for preventing pregnancies. It can typically be used for several years and can be taken out easily if you want to become pregnant. But, iuds do not prevent sexually transmitted infections. Condoms should always be used to prevent sexually transmitted infections.