This depends on the species, on the route of administration and on the contraceptive. Injectable immunocontraceptives which are effective after a single dose, may last a lifetime or require re-administration every 1-3 years to maintain infertility. A single levonorgestrel implant maintains infertility in several marsupial species for several years.

VCD-based oral contraceptives for rats require several weeks of continuous administration in bait to have an effect on fertility. Contraceptives based on a combination of levonorgestrel and quinestrol require one week of continuous administration to affect rodents’ reproduction. Nicarbazin must be delivered to pigeons continuously throughout the reproductive season to maintain infertility.