title: Ovarian function during use of vaginal rings delivering three different doses of Nestorone.
abstract: Contraceptive vaginal rings delivering various progestins alone or in combination with estrogen have been previously studied, showing adequate steroid vaginal absorption and acceptability by the users. Nestorone progestin (NES) is a potent 19-nor-progesterone derivative, inactive by the oral route, but an excellent option for vaginal delivery. The purpose of this study was to evaluate ovarian function during 6 months of continuous use of progestin-only vaginal rings delivering 3 different doses of NES: 50, 75, and 100 microg per day. Blood samples were taken twice a week for 5 consecutive weeks during a control cycle and on months 1, 3 and 6 of use, for the measurement of estradiol (E2), progesterone (P), and NES. A total of 87 volunteers randomly received each of the 3 doses. After an initial peak, NES serum levels remained fairly constant throughout the duration of the study at about 125, 200 and 250 pmol/L, respectively, decreasing slightly with time. Luteal activity occurred very rarely (1.2-2.6% of sampling periods) with no apparent difference between doses. Low E2 levels (< or =100 pmol/L) in all samples of a run were rare (5%) and only with the high dose ring (100 microg/day). E2 remained within normal levels (101-1500 pmol/L) in most of the segments studied. We conclude that the 50 and 75 microg/day NES rings provide adequate ovulation inhibition without hypoestrogenism, while the 100 microg/day ring may deliver an unnecessarily high dose.
authors.affiliation: PROFAMILIA, Santo Domingo, Dominican Republic. biomedica@codetel.net.do
authors.forename: V
authors.initials: V
authors.lastname: Brache
authors.forename: D R
authors.initials: DR
authors.lastname: Mishell
authors.forename: P
authors.initials: P
authors.lastname: Lahteenmaki
authors.forename: F
authors.initials: F
authors.lastname: Alvarez
authors.forename: K
authors.initials: K
authors.lastname: Elomaa
authors.forename: T
authors.initials: T
authors.lastname: Jackanicz
authors.forename: A
authors.initials: A
authors.lastname: Faundes
mesh_terms: D000282:Administration, Intravaginal; D000293:Adolescent; D000328:Adult; D003271:Contraceptive Agents, Female / Q000008:administration & dosage* / Q000097:blood; D003274:Contraceptive Devices, Female; D004343:Drug Implants; D004958:Estradiol / Q000097:blood / Q000378:metabolism; D005260:Female; D006801:Humans; D009653:Norprogesterones / Q000008:administration & dosage* / Q000097:blood; D010053:Ovary / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D011374:Progesterone / Q000097:blood / Q000378:metabolism
chemical_list: D003271:Contraceptive Agents, Female; D004343:Drug Implants; D009653:Norprogesterones; D011374:Progesterone; D004958:Estradiol; C029167:ST 1435