Contraceptives, Oral, Synthetic: Oral contraceptives which owe their effectiveness to synthetic preparations.Mestranol: The 3-methyl ether of ETHINYL ESTRADIOL. It must be demethylated to be biologically active. It is used as the estrogen component of many combination ORAL CONTRACEPTIVES.Contraceptives, Oral: Compounds, usually hormonal, taken orally in order to block ovulation and prevent the occurrence of pregnancy. The hormones are generally estrogen or progesterone or both.Norgestrel: A synthetic progestational agent with actions similar to those of PROGESTERONE. This racemic or (+-)-form has about half the potency of the levo form (LEVONORGESTREL). Norgestrel is used as a contraceptive, ovulation inhibitor, and for the control of menstrual disorders and endometriosis.Contraceptive Agents: Chemical substances that prevent or reduce the probability of CONCEPTION.Contraceptives, Oral, Combined: Fixed drug combinations administered orally for contraceptive purposes.Norethindrone: A synthetic progestational hormone with actions similar to those of PROGESTERONE but functioning as a more potent inhibitor of ovulation. It has weak estrogenic and androgenic properties. The hormone has been used in treating amenorrhea, functional uterine bleeding, endometriosis, and for contraception.Ethynodiol Diacetate: A synthetic progestational hormone used alone or in combination with estrogens as an oral contraceptive.Spermatogenesis-Blocking Agents: Chemical substances which inhibit the process of spermatozoa formation at either the first stage, in which spermatogonia develop into spermatocytes and then into spermatids, or the second stage, in which spermatids transform into spermatozoa.Ethinyl Estradiol: A semisynthetic alkylated ESTRADIOL with a 17-alpha-ethinyl substitution. It has high estrogenic potency when administered orally, and is often used as the estrogenic component in ORAL CONTRACEPTIVES.Lynestrenol: A synthetic progestational hormone used often in mixtures with estrogens as an oral contraceptive.Contraceptive Agents, Female: Chemical substances or agents with contraceptive activity in females. Use for female contraceptive agents in general or for which there is no specific heading.Ethinyl Estradiol-Norgestrel Combination: ETHINYL ESTRADIOL and NORGESTREL given in fixed proportions. It has proved to be an effective contraceptive (CONTRACEPTIVES, ORAL, COMBINED).XanthurenatesContraceptives, Oral, Hormonal: Oral contraceptives which owe their effectiveness to hormonal preparations.Spermatocidal Agents: Chemical substances that are destructive to spermatozoa used as topically administered vaginal contraceptives.Contraceptive Agents, Male: Chemical substances or agents with contraceptive activity in males. Use for male contraceptive agents in general or for which there is no specific heading.Contraceptive Devices: Devices that diminish the likelihood of or prevent conception. (From Dorland, 28th ed)Contraception: Prevention of CONCEPTION by blocking fertility temporarily, or permanently (STERILIZATION, REPRODUCTIVE). Common means of reversible contraception include NATURAL FAMILY PLANNING METHODS; CONTRACEPTIVE AGENTS; or CONTRACEPTIVE DEVICES.Pyridoxine: The 4-methanol form of VITAMIN B 6 which is converted to PYRIDOXAL PHOSPHATE which is a coenzyme for synthesis of amino acids, neurotransmitters (serotonin, norepinephrine), sphingolipids, aminolevulinic acid. Although pyridoxine and Vitamin B 6 are still frequently used as synonyms, especially by medical researchers, this practice is erroneous and sometimes misleading (EE Snell; Ann NY Acad Sci, vol 585 pg 1, 1990).Menstruation: The periodic shedding of the ENDOMETRIUM and associated menstrual bleeding in the MENSTRUAL CYCLE of humans and primates. Menstruation is due to the decline in circulating PROGESTERONE, and occurs at the late LUTEAL PHASE when LUTEOLYSIS of the CORPUS LUTEUM takes place.Contraceptive Devices, Female: Contraceptive devices used by females.Contraception Behavior: Behavior patterns of those practicing CONTRACEPTION.Riboflavin: Nutritional factor found in milk, eggs, malted barley, liver, kidney, heart, and leafy vegetables. The richest natural source is yeast. It occurs in the free form only in the retina of the eye, in whey, and in urine; its principal forms in tissues and cells are as FLAVIN MONONUCLEOTIDE and FLAVIN-ADENINE DINUCLEOTIDE.Nutrition Disorders: Disorders caused by nutritional imbalance, either overnutrition or undernutrition.Intrauterine Devices: Contraceptive devices placed high in the uterine fundus.Family Planning Services: Health care programs or services designed to assist individuals in the planning of family size. Various methods of CONTRACEPTION can be used to control the number and timing of childbirths.Copper: A heavy metal trace element with the atomic symbol Cu, atomic number 29, and atomic weight 63.55.Desogestrel: A synthetic progestational hormone used often as the progestogenic component of combined oral contraceptive agents.Levonorgestrel: A synthetic progestational hormone with actions similar to those of PROGESTERONE and about twice as potent as its racemic or (+-)-isomer (NORGESTREL). It is used for contraception, control of menstrual disorders, and treatment of endometriosis.Contraceptives, Postcoital: Contraceptive substances to be used after COITUS. These agents include high doses of estrogenic drugs; progesterone-receptor blockers; ANTIMETABOLITES; ALKALOIDS, and PROSTAGLANDINS.Zinc: A metallic element of atomic number 30 and atomic weight 65.38. It is a necessary trace element in the diet, forming an essential part of many enzymes, and playing an important role in protein synthesis and in cell division. Zinc deficiency is associated with ANEMIA, short stature, HYPOGONADISM, impaired WOUND HEALING, and geophagia. It is known by the symbol Zn.Vaccines, Contraceptive: Vaccines or candidate vaccines used to prevent conception.Pregnancy, Unplanned: Unintended accidental pregnancy, including pregnancy resulting from failed contraceptive measures.Sterilization, Reproductive: Procedures to block or remove all or part of the genital tract for the purpose of rendering individuals sterile, incapable of reproduction. Surgical sterilization procedures are the most commonly used. There are also sterilization procedures involving chemical or physical means.Pregnancy, Unwanted: Pregnancy, usually accidental, that is not desired by the parent or parents.Medroxyprogesterone Acetate: A synthetic progestin that is derived from 17-hydroxyprogesterone. It is a long-acting contraceptive that is effective both orally or by intramuscular injection and has also been used to treat breast and endometrial neoplasms.Contraception, Postcoital: Means of postcoital intervention to avoid pregnancy, such as the administration of POSTCOITAL CONTRACEPTIVES to prevent FERTILIZATION of an egg or implantation of a fertilized egg (OVUM IMPLANTATION).Intrauterine Devices, Copper: Intrauterine contraceptive devices that depend on the release of metallic copper.Norethynodrel: A synthetic progestational hormone with actions and uses similar to those of PROGESTERONE. It has been used in the treatment of functional uterine bleeding and endometriosis. As a contraceptive, it has usually been administered in combination with MESTRANOL.Pregnancy: The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.Abortion, Induced: Intentional removal of a fetus from the uterus by any of a number of techniques. (POPLINE, 1978)Contraception, Immunologic: Contraceptive methods based on immunological processes and techniques, such as the use of CONTRACEPTIVE VACCINES.Norpregnenes: Pregnenes with one double bond or more than three double bonds which have undergone ring contractions or are lacking carbon-18 or carbon-19..Progestins: Compounds that interact with PROGESTERONE RECEPTORS in target tissues to bring about the effects similar to those of PROGESTERONE. Primary actions of progestins, including natural and synthetic steroids, are on the UTERUS and the MAMMARY GLAND in preparation for and in maintenance of PREGNANCY.Contraceptives, Oral, Sequential: Drugs administered orally and sequentially for contraceptive purposes.Contraceptives, Postcoital, Hormonal: Postcoital contraceptives which owe their effectiveness to hormonal preparations.Sterilization, Tubal: Procedures that render the female sterile by interrupting the flow in the FALLOPIAN TUBE. These procedures generally are surgical, and may also use chemicals or physical means.Androstenes: Unsaturated derivatives of the steroid androstane containing at least one double bond at any site in any of the rings.Menstrual Cycle: The period from onset of one menstrual bleeding (MENSTRUATION) to the next in an ovulating woman or female primate. The menstrual cycle is regulated by endocrine interactions of the HYPOTHALAMUS; the PITUITARY GLAND; the ovaries; and the genital tract. The menstrual cycle is divided by OVULATION into two phases. Based on the endocrine status of the OVARY, there is a FOLLICULAR PHASE and a LUTEAL PHASE. Based on the response in the ENDOMETRIUM, the menstrual cycle is divided into a proliferative and a secretory phase.Progesterone Congeners: Steroidal compounds related to PROGESTERONE, the major mammalian progestational hormone. Progesterone congeners include important progesterone precursors in the biosynthetic pathways, metabolites, derivatives, and synthetic steroids with progestational activities.Parity: The number of offspring a female has borne. It is contrasted with GRAVIDITY, which refers to the number of pregnancies, regardless of outcome.Intrauterine Devices, Medicated: Intrauterine devices that release contraceptive agents.Health Knowledge, Attitudes, Practice: Knowledge, attitudes, and associated behaviors which pertain to health-related topics such as PATHOLOGIC PROCESSES or diseases, their prevention, and treatment. This term refers to non-health workers and health workers (HEALTH PERSONNEL).Contraceptive Devices, Male: Contraceptive devices used by males.Pregnancy in Adolescence: Pregnancy in human adolescent females under the age of 19.Menstruation Disturbances: Variations of menstruation which may be indicative of disease.Megestrol: 17-Hydroxy-6-methylpregna-3,6-diene-3,20-dione. A progestational hormone used most commonly as the acetate ester. As the acetate, it is more potent than progesterone both as a progestagen and as an ovulation inhibitor. It has also been used in the palliative treatment of breast cancer.Contraceptives, Postcoital, Synthetic: Postcoital contraceptives which owe their effectiveness to synthetic preparations.Drug Implants: Small containers or pellets of a solid drug implanted in the body to achieve sustained release of the drug.Sex Education: Education which increases the knowledge of the functional, structural, and behavioral aspects of human reproduction.Ovulation Inhibition: Blocking the process leading to OVULATION. Various factors are known to inhibit ovulation, such as neuroendocrine, psychological, and pharmacological agents.Medroxyprogesterone: (6 alpha)-17-Hydroxy-6-methylpregn-4-ene-3,20-dione. A synthetic progestational hormone used in veterinary practice as an estrus regulator.Fertility: The capacity to conceive or to induce conception. It may refer to either the male or female.Condoms: A sheath that is worn over the penis during sexual behavior in order to prevent pregnancy or spread of sexually transmitted disease.Sexual Behavior: Sexual activities of humans.Norpregnadienes: Pregnadienes which have undergone ring contractions or are lacking carbon-18 or carbon-19.Transdermal Patch: A medicated adhesive patch placed on the skin to deliver a specific dose of medication into the bloodstream.Ethisterone: 17 alpha-Hydroxypregn-4-en-20-yn-3-one. A synthetic steroid hormone with progestational effects.Uterine Hemorrhage: Bleeding from blood vessels in the UTERUS, sometimes manifested as vaginal bleeding.Estradiol Congeners: Steroidal compounds related to ESTRADIOL, the major mammalian female sex hormone. Estradiol congeners include important estradiol precursors in the biosynthetic pathways, metabolites, derivatives, and synthetic steroids with estrogenic activities.Metrorrhagia: Abnormal uterine bleeding that is not related to MENSTRUATION, usually in females without regular MENSTRUAL CYCLE. The irregular and unpredictable bleeding usually comes from a dysfunctional ENDOMETRIUM.Risk Factors: An aspect of personal behavior or lifestyle, environmental exposure, or inborn or inherited characteristic, which, on the basis of epidemiologic evidence, is known to be associated with a health-related condition considered important to prevent.Estrogens: Compounds that interact with ESTROGEN RECEPTORS in target tissues to bring about the effects similar to those of ESTRADIOL. Estrogens stimulate the female reproductive organs, and the development of secondary female SEX CHARACTERISTICS. Estrogenic chemicals include natural, synthetic, steroidal, or non-steroidal compounds.Nonoxynol: Nonionic surfactant mixtures varying in the number of repeating ethoxy (oxy-1,2-ethanediyl) groups. They are used as detergents, emulsifiers, wetting agents, defoaming agents, etc. Nonoxynol-9, the compound with 9 repeating ethoxy groups, is a spermatocide, formulated primarily as a component of vaginal foams and creams.Coitus: The sexual union of a male and a female, a term used for human only.Abortion Applicants: Individuals requesting induced abortions.Abortion, Legal: Termination of pregnancy under conditions allowed under local laws. (POPLINE Thesaurus, 1991)Reproductive Health Services: Health care services related to human REPRODUCTION and diseases of the reproductive system. Services are provided to both sexes and usually by physicians in the medical or the surgical specialties such as REPRODUCTIVE MEDICINE; ANDROLOGY; GYNECOLOGY; OBSTETRICS; and PERINATOLOGY.Age Factors: Age as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or the effect of a circumstance. It is used with human or animal concepts but should be differentiated from AGING, a physiological process, and TIME FACTORS which refers only to the passage of time.Marriage: The social institution involving legal and/or religious sanction whereby individuals are joined together.Case-Control Studies: Studies which start with the identification of persons with a disease of interest and a control (comparison, referent) group without the disease. The relationship of an attribute to the disease is examined by comparing diseased and non-diseased persons with regard to the frequency or levels of the attribute in each group.