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Ovulatory dysfunction during continuous administration of low-dose levonorgestrel by subdermal implants.
A Faundes1, V Brache, A S Tejada
1PROFAMILIA, Santo Domingo, Dominican Republic.
Fertility and Sterility
|July 1, 1991
Summary
Levonorgestrel implants disrupt ovulation in nearly half of users. Even in cycles with ovulation, hormonal imbalances contribute to Norplant's high contraceptive effectiveness.
Area of Science:
- Reproductive Endocrinology
- Contraceptive Technology
Background:
- Levonorgestrel subdermal implants (Norplant) are a long-acting reversible contraceptive method.
- Understanding the endocrinologic mechanisms underlying Norplant's efficacy is crucial.
Purpose of the Study:
- To investigate the hormonal profiles of women using levonorgestrel implants.
- To assess the impact of Norplant on the menstrual cycle endocrinology.
Main Methods:
- Prospective, case-controlled study involving 31 Norplant users and 12 nonhormonal contraceptive users.
- Serial assays of follicle-stimulating hormone, luteinizing hormone, estradiol, and progesterone over one menstrual cycle.
Main Results:
- Nearly 50% of cycles in Norplant users were anovulatory.
- The remaining 55% of cycles exhibited luteal phase insufficiency and altered estradiol profiles.
- Diminished gonadotropin surges were also observed.
Conclusions:
- Anovulation is a primary mechanism of action for levonorgestrel implants.
- Hormonal dysfunctions in presumptive ovulatory cycles likely enhance contraceptive effectiveness.
Keywords:
AmericasBiologyCaribbeanCase Control StudiesContraceptionContraceptive Agents, Female--administraction and dosageContraceptive Agents, Female--side effectsContraceptive Agents, Progestin--administraction and dosageContraceptive Agents, Progestin--side effectsContraceptive Agents--administraction and dosageContraceptive Agents--side effectsContraceptive Implants--administraction and dosageContraceptive Methods--administraction and dosageContraceptive Mode Of ActionDeveloping CountriesDominican RepublicEndocrine System--changesEstradiol--analysisEstrogensExaminations And DiagnosesFamily PlanningFollicle Stimulating Hormone--analysisGonadotropinsGonadotropins, PituitaryHormonesLaboratory Examinations And DiagnosesLatin AmericaLevonorgestrel--administraction and dosageLevonorgestrel--side effectsLuteinizing Hormone--analysisNorth AmericaOvulationPhysiologyProgestational HormonesProgesterone--analysisProspective StudiesReproductionResearch MethodologyStudies