title: Endometrial effects of etonogestrel (Implanon) contraceptive implant.
abstract: The subdermal contraceptive implant etonogestrel (Implanon; NV Organon International, Oss, The Netherlands) exerts complex effects on the endometrium. These include direct effects on the endometrium through endometrial progestin target sites, and indirect effects through suppression of the hypothalamic-pituitary-ovarian axis. The resulting effects are categorized by alterations in endometrial histology, endometrial thickness, dysmenorrhoea and menstrual bleeding pattern. The exact mechanism of action of progestins on the endometrium has not been determined. The contraceptive effect in Implanon users is mainly due to inhibition of ovulation. Current research is concentrating on the potential of the progestin implant to modify endometrial vascular, angiogenic, steroid receptor and proto-oncogene function. These processes may be involved in the causation of progestin-induced breakthrough bleeding.
authors.affiliation: Department of Obstetrics and Gynaecology, Luton and Dunstable NHS Trust, Luton, UK. rajesh.varma@ldh-tr.anglox.nhs.uk
authors.forename: R
authors.initials: R
authors.lastname: Varma
authors.forename: L
authors.initials: L
authors.lastname: Mascarenhas
mesh_terms: D003271:Contraceptive Agents, Female / Q000494:pharmacology*; D017135:Desogestrel; D004343:Drug Implants; D004717:Endometrium / Q000187:drug effects* / Q000503:physiopathology; D005260:Female; D006801:Humans; D000090063:Proto-Oncogene Mas; D014753:Vinyl Compounds / Q000494:pharmacology*
chemical_list: D003271:Contraceptive Agents, Female; D004343:Drug Implants; C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D014753:Vinyl Compounds; C044815:etonogestrel; D017135:Desogestrel