Progestin-only methods are very effective
Keller, S.
Network 15(4): 4-8
1995
ISSN/ISBN: 0270-3637 PMID: 12289832 Document Number: 290991
Modeled after the naturally occurring hormone progesterone, progestins are the synthetic hormones used in Norplant, depot-medroxyprogesterone acetate (DMPA), and progestin-only pills (POPs). Progestin-only contraceptives alter a woman's hormonal balance. In so doing, progestin-only contraceptives block a series of chemical signals essential to the completion of a normal reproductive cycle, either by blocking the release of an egg or by making its fertilization and implantation within the uterus unlikely. In many women, progestin-only contraceptives stop the monthly release of an egg. Even if an egg is released, progestin makes its movement through the fallopian tubes into the uterus more difficult. Progestin also thickens the mucus in the cervix, which stops sperm from penetrating the mucus and reaching an egg. In the unlikely event that ovulation does occur and an egg becomes fertilized, the hormonal disruption makes the lining of the uterus inhospitable for implantation. This multiple mode of action therefore makes progestin-only methods among the most reliable of all contraceptives. Norplant and progestin-only injectables have failure rates of less than 1%, while POPs are typically 95% effective. Sections discuss ovulatory suppression, physiological changes, weight gain and headaches, health concerns, and counseling before use.