Delivery of progestins via the subdermal versus the intrauterine route: comparison of the pharmacology and clinical outcomes.

INTRODUCTION: Subdermal and intrauterine progestin releasing systems are two types of long-acting reversible contraceptive systems (LARC). Their use has transformed current contraceptive practice management. There is not much objective evidence to help decide which method is preferable and in which particular circumstance using objective criteria. Areas covered: MEDLINE, POPLINE, PubMed, and clinicaltrials.gov were searched using the terms "implant" vs "IUS" and then adding the terms "levonorgestrel" and "etonogestrel" to the implant arm and "levonorgestrel" to the IUS arm. This was done using commercial names as well for the terms "pharmacodynamics" and "pharmacokinetics" as well as for the term "therapeutic." Preference was given to comparative studies of the highest degree. Expert opinion: Under normal circumstances, user satisfaction appeared marginally greater for intrauterine rather than subdermal progestin provision. However, after uterine events such as pregnancy or surgical evacuation of the uterus, implants performed better. Intrauterine progestin is preferable for therapeutic purposes.