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Chemical contraception – Hormonal contraception

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Hormonal contraception refers to birth control methods that act on the hormonal system.

Currently, all hormonal contraceptives are designed for use by women rather than men, though research on a male hormonal contraceptive (“the male Pill”) has been underway for some time.

Hormonal contraceptives may be introduced into the woman’s body in many different ways, among them orally, vaginally, transdermally, or through injections or implants. The oral method was the first and most famous of these; within a few years of its introduction in 1960, “the Pill” became one of the most popular contraceptives in the United States and elsewhere, and it remains so today.

Hormonal contraception may act in one or more ways to prevent pregnancy. It may cause ovulation to cease, preventing the possibility of fertilization; it may thicken the woman’s cervical mucus, making penetration of the uterus by sperm more difficult; or it may alter and thin the endometrium so that a fertilized egg has difficulty implanting. (Technically, if the drug works in this third fashion, it acts as a contragestive rather than a contraceptive, since it has not prevented conception, acting instead to prevent gestation.)


  • If used properly, hormonal contraceptives are highly effective; except for abstinence, vasectomy, and tubal ligation, no other method of birth control has as great a degree of effectiveness.
  • Hormonal contraceptives allow spontaneous intercourse.


  • Hormonal contraceptives offer no protection against sexually transmitted infections, placing non-monogamous individuals and couples at high risk for contracting such an infection.
  • Like many other forms of birth control, hormonal contraceptives rely on the woman to use them correctly. Some, such as implants, require relatively little attention; others, such as injections or transdermal patches, require a schedule ranging from a week to several months. Still others—the wide varieties of oral contraception require a daily schedule. For example, many patient information leaflet for these pharmaceuticals suggest using a back up method of birth control if 2 or more doses are missed.
  • Hormonal contraceptives can have side effects, including: weight gain, loss of libido, hair loss, mood swings, bleeding between periods, nausea, breast tenderness, headaches, mastalgia, depression, ovarian cysts, constant bleeding (metrorrhagia), panic attacks, muscle pain, heart palpitations, pain during sex, acne, abdominal cramps, dizziness, weakness or fatigue, leg cramps, nausea, vaginal discharge or irritation, bloating, swelling of the hands or feet, backache,insomnia, pelvic pain, rash, hot flashes,joint pain, convulsions, jaundice, urinary tract infections, and allergic reactions.
  • Hormonal contraceptives can have serious health risks, such as ectopic pregnancy, decreased bone density, deep vein thrombosis, pulmonary embolus, uterine perforation, blood clot/stroke (stroke intensified risk for women who smoke) and death.
  • Artificial contraception is objectionable to some religious traditions. These objections are furthered by the suggested, yet unproven post-fertilisation mode of action of preventing the implantation of a blastocyst.
  • Hormonal contraceptives require a prescription in the United States and most other countries because of potential health risks.

Effects on rates of cancers

There is a mixed effect of combined hormonal contraceptives on the rates of various cancers, with the International Agency for Research on Cancer (IARC) concluding that “Combined oral contraceptives are carcinogenic to humans” and that “there is also conclusive evidence that these agents have a protective effect against cancers of the ovary and endometrium”:

  • The (IARC) note that “the weight of the evidence suggests a small increase in the relative risk for breast cancer among current and recent users” which following discontinuation then lessens over a period of 10 years to similar rates as women who never used them.
  • Small increases are also seen in the rates of cervical cancer and hepatocellular (liver) tumours.
  • Endometrial and ovarian cancer risks are approximately halved and persists for at least 10 years after cessation of use; although “sequential oral contraceptives which were removed from the consumer market in the 1970s was associated with an increased risk for endometrial cancer”.
  • Studies have overall not shown effects on the relative risks for colorectal, malignant melanoma or thyroid cancers.
  • Numerous studies have shown carcinogenicity in experimental animals.

Types of Hormonal Contraception

Oral Contraceptives

  • Combined oral contraceptive pill — known colloquially as “The Pill”, it is a combined estrogen and progesterone pill which is taken daily at the same time.
  • Progesterone only pill (POP)

Non-surgical devices

  • Contraceptive patch – an adhesive patch containing hormones which is applied to the skin and worn continuously. It is changed each week for three weeks and removed for one week.
  • Contraceptive vaginal ring (“NuvaRing”) – a flexible ring containing estrogen and progesterone, it is inserted into the vagina and worn for three continuous weeks, removed for one week, then replaced with a new ring.

Surgical devices

  • Implants – a set of small, flexible rods which contain progesterone, which are implanted under the skin. Norplant, an implant of this type, is being phased out of production, though Implanon, a newer implant, was approved in July of 2006, and Jadelle was approved in 1996.
  • Progesterone IntraUterine System – otherwise known as the IUS, this device is inserted into the uterus by a health care professional, where it continuously releases progesterone. It remains in the uterus for a period of years, as determined by the manufacturer.


  • Lunelle – a monthly injection of progesterone, not currently available for sale.
  • Depo Provera – an injection of progesterone administered every three months.

Most combined and progesterone-only pills may also be taken in high doses as emergency contraception (also known as the morning after pill). However, unlike plain copper IUDs, hormonal IUS is not approved for emergency contraception.


Centchroman is sometimes mistaken for a hormonal contraceptive, probably because it is a pill that prevents pregnancy. Although it may be correctly termed a ‘weekly contraceptive pill’, it is not a hormonal contraceptive. Centchroman is a Selective Estrogen Receptor Modulator, or SERM. It causes ovulation to occur sooner than it normally would, while causing the lining of the uterus to build more slowly, which, together, prevent pregnancy. Centchroman is legally available only in India.

Licensed under the GNU Free Documentation License. It uses materials from the Wikipedia.

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