Oral contraceptive
Oral contraceptives are chemicals taken by mouth to inhibit normal fertility. All act on the hormonal system. Female oral contraceptives have been on the market since the early 1960s, and enjoy great popularity. It is used by millions of women around the world, though the acceptance varies by region: approximately one-third of sexually active women in the United Kingdom, but much less in countries such as Japan. Male oral contraceptives remain a subject of research and development, and are not widely available to the public.
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Principles
Female oral contraceptives, colloquially known as the Pill, are the most common form of pharmaceutical contraception. They are used to prevent pregnancy. The pill can also be used to control dysfunctional bleeding or symptoms of polycystic ovary syndrome. They consist of a pill that women take daily and that contains doses of synthetic hormones (always a progestin and most often also an estrogen). In some types of pill the doses of hormones are adjusted to be in synchrony with the menstrual cycle (two- or three-phase pills), while others keep a constant level of the hormones.
Mechanism of action
The Pill works by preventing ovulation, as well as making the uterus less likely to accept implantation of an embryo if one is created, and thickens the mucus in the cervix making it more difficult for sperm to reach any egg.
Several different types of 'the Pill' exist. Generally, they all have revolved around different synthetic estrogens and progestins, chemical analogues of the natural hormones estradiol (an estrogen) and progesterone (a progestagen). Most common brands use 20 to 40 micrograms of ethinyl estradiol as the estrogen component and either a fixed or varying (the bi- and triphasic pills) amount of either levonorgestrel or norethindrone as the progestagen component.
Effectiveness
The Pearl Indexpregnant during one year of perfect use (Pearl index = 0.3 to 1.25).
While the Pill is usually effective, its wide availability has not prevented what some call "unwanted pregnancies". In the USA, the rise in widespread use of the Pill has coincided with a rise in the abortion rate to a level that is consistently above 1,000,000 per year, according to AGI statistics. This can be attributed to an increased expectation that sexual intercourse never needs to result in the birth of a baby, even if contraception fails.
Packaging
Pillpacketopen.jpg
The Pill usually comes in two different packet sizes, and each packet usually has days marked off for a cycle lasting of 28 days. For the 21-pill packet, a woman takes a pill each day for 21 days, and waits for an additional seven days before starting the next packet. For the 28-pill packet, the woman similarly takes a pill each day. However, instead of only taking pills for 21 days of the month, she also takes the remaining seven placebo or sugar pills included in the packet, and once she finishes the last placebo pill, she can immediately start the next packet on the following day. The purpose of the placebo pills is to ensure that the woman, out of habit, can take a pill on every day of her menstrual cycle, so that she does not have to calculate when exactly is the next date that she should start her next packet of pills. It is possible for a woman to skip menstruation and still remain protected against conception by skipping these pills in the cycle. The presence of these pills is still thought to be comforting for the woman as menstruation is a physical confirmation that she is still not pregnant.
Drug interactions
Some drugs reduce the effect of the Pill and can cause breakthrough bleeding, or pregnancy (together with unprotected sex, of course). These include antibiotics, barbiturates, phenytoin and carbamazepine. The traditional medicinal drug St John's Wort has also been implicated.
Side-effects
When starting to take the birth control Pill some women report slight weight gain, although this depends entirely on the individual and some people experience no weight gain at all while people who are already obese or overweight may continue to gain weight. Some people also notice changes in the intensity of sexual desire, vaginal discharge and menstrual flow.
Some other common side effects are: nausea, headaches, depression, vaginitis, urinary tract infection, changes in the breasts, skin problems, and gum inflammation.
Cautions and contraindications
Oral contraceptives may influence coagulation, increasing the risk of blood clots causing deep venous thrombosis (DVT) and pulmonary embolism, stroke and myocardial infarction (heart attack). This is especially so in women who already have some pre-existing cardiovascular disease, in women who have a familial tendency to form blood clots (such as familial factor V Leiden), women with obesity or hypercholesterolaemia (high cholesterol level) and in smokers.
The Pill has also been linked to an increased risk of breast cancer, although newer Pill types may not influence breast cancer risk. In rare cases, high estrogen Pills may trigger benign intracranial hypertension. Women who use the Pill have an increased chance of developing certain serious problems that can be fatal. Benign liver tumors have been reported.
The chance of developing most of the above problems increases with age - especially when certain other health problems are present. The risks are even greater for women who are age 35 or older, smoke more than 15 cigarettes a day, or have conditions associated with heart attack, such as diabetes, high blood pressure, or high levels of cholesterol, and certain inherited conditions that increase the risk of blood clotting. Women using the Pill who undergo major surgery seem to have a greater chance of having blood clots.
Benefits
Aside from being a contraceptive and for management of irregular periods, there may be incidental benefits to the Pill. There is some evidence that use of the pill might reduce the incidence of ovarian cancer and endometrial cancer breast cancer or deep-vein thrombosis.
History
The invention
Carl Djerassi (1923-) invented norethindrone in the 1950s. The Pill was developed in the 1950s by Gregory Pincus with the encouragement and financial backing of birth control activists Margaret Sanger and Katharine McCormick.
The FDA approved it for clinical use on May 9, 1960. It took various high-profile court cases, such as Poe v. Ullman and Griswold v. Connecticut, to make it available to all women of reproductive age.
France
The Pill was rendered legal in 1967 after the introduction of the Neuwirth Law.
Japan
In Japan, continual debates over safety and sexually-transmitted infection risks (raised over concerns that oral contraceptive use will diminish condom use) have led to the Pill being banned for nearly 40 years, and its recent introduction has seen very few women take it up^ Pearl R. Factors in human fertility and their statistical evaluation. Lancet 1933;2:607-611.
See also
See also: Oral contraceptive, 1923, 1950s, 1960, 1960s, Antibiotics, Arterial hypertension, Barbiturate