The combined oral contraceptive pill (COCP), often referred to as the birth-control pill or colloquially as "the Pill", is a birth control method that includes a combination of an estrogen (estradiol) and a progestogen (progestin). When taken by mouth every day, these pills inhibit female fertility. They were first approved for contraceptive use in the United States in 1960, and are a very popular form of birth control. They are currently used by more than 100 million women worldwide and by almost 12 million women in the United States. Use varies widely by country, age, education, and marital status: one third of women aged 16–49 in the United Kingdom currently use either the combined pill or a progestogen-only "minipill", compared to only 1% of women in Japan.
Combined oral contraceptive pills should be taken at the same time each day. If one or more tablets are forgotten for more than 12 hours, contraceptive protection will be reduced. Most brands of combined pills are packaged in one of two different packet sizes, with days marked off for a 28 day cycle. For the 21-pill packet, a pill is consumed daily for three weeks, followed by a week of no pills. For the 28-pill packet, 21 pills are taken, followed by week of placebo or sugar pills. A woman on the pill will have a withdrawal bleed sometime during the placebo week, and is still protected from pregnancy during this week. There are also two newer combination birth control pills (Yaz 28 and Loestrin 24 Fe) that have 24 days of active hormone pills, followed by 4 days of placebo.
Slow Decay is a BBC Books original novel written by Andy Lane and based on the British science fiction television, Doctor Who spin-off series Torchwood. It features all the regular cast of the show.
Gwen has made a dinner date with Rhys, but Jack advises her to keep her mobile on, as Toshiko is tracking an alien energy signature somewhere in Cardiff and the team may be called into action at any moment. Gwen is irritated both by the thought that her date might be interrupted, and by the fact that Owen stands rather too close when they take the invisible lift up out of the Hub. She is thus in a bad enough mood when she arrives at the Indian Summer restaurant to find Rhys chatting with a beautiful young woman who turns out to be his co-worker Lucy. It takes Gwen a moment to recognise Lucy, who has lost a great deal of weight since they last met—and although Rhys claims that Lucy just needed cheering up as she's going through a rough patch with her boyfriend, Gwen notices with some unease that Lucy is quite obviously flirting with Rhys.
Hormonal contraception refers to birth control methods that act on the endocrine system. Almost all methods are composed of steroid hormones, although in India one selective estrogen receptor modulator is marketed as a contraceptive. The original hormonal method—the combined oral contraceptive pill—was first marketed as a contraceptive in 1960. In the ensuing decades many other delivery methods have been developed, although the oral and injectable methods are by far the most popular. Altogether, 18% of the world's contraceptive users rely on hormonal methods. Hormonal contraception is highly effective: when taken on the prescribed schedule, users of steroid hormone methods experience pregnancy rates of less than 1% per year. Perfect-use pregnancy rates for most hormonal contraceptives are usually around the 0.3% rate or less. Currently available methods can only be used by women; the development of a male hormonal contraceptive is an active research area.
There are two main types of hormonal contraceptive formulations: combined methods which contain both an estrogen and a progestin, and progestogen-only methods which contain only progesterone or one of its synthetic analogues (progestins). Combined methods work by suppressing ovulation and thickening cervical mucus; while progestogen-only methods reduce the frequency of ovulation, most of them rely more heavily on changes in cervical mucus. The incidence of certain side effects is different for the different formulations: for example, breakthrough bleeding is much more common with progestogen-only methods. Certain serious complications occasionally caused by estrogen-containing contraceptives are not believed to be caused by progestogen-only formulations: deep vein thrombosis is one example of this.
Menstrual cycle is the cycle of changes that occurs in the uterus and ovary for the purpose of sexual reproduction. It is essential for the production of eggs and for the preparation of the uterus for pregnancy. The menstrual cycle occurs only in fertile female humans and other female primates.
In humans, the length of a menstrual cycle varies greatly among women (ranging from 25 to 35 days), with 28 days designated as the average length. Each cycle can be divided into three phases based on events in the ovary (ovarian cycle) or in the uterus (uterine cycle). The ovarian cycle consists of the follicular phase, ovulation, and luteal phase whereas the uterine cycle is divided into menstruation, proliferative phase, and secretory phase. Both cycles are controlled by the endocrine system and the normal hormonal changes that occur can be interfered with using hormonal contraception to prevent reproduction.
Combined estrogrogen/progestin pills of Yuzpe regimen now superseded by better-tolerated and more effective progestin-only pill.
Progestin only ECP licensed for use within 3 days of unprotected intercourse, Ulipristal acetate and IUDs within 5 days.
Emergency contraception (EC), or emergency postcoital contraception, are birth control measures that, if taken after sexual intercourse, may prevent pregnancy.