Menstruation

Menstruation is the shedding of the uterine lining (endometrium). It occurs on a regular basis in reproductive age females of certain mammal species. Overt menstruation (where there is bleeding from the vagina) is found primarily in humans and close evolutionary relatives such as chimpanzees.[1] The females of other placental mammal species have estrous cycles, in which the endometrium is reabsorbed by the animal (covert menstruation) at the end of its reproductive cycle. Many zoologists regard this as different from a "true" menstrual cycle. As part of the menstrual cycle Main article: Menstrual cycle Menstruation is the most visible phase of the menstrual cycle. Menstrual cycles are counted from the first day of menstrual bleeding, because the onset of menstruation corresponds closely with the hormonal cycle. During pregnancy and for some time after childbirth, menstruation is normally suspended; this state is known as amenorrhoea, i.e. absence of the menstrual cycle. If menstruation has not resumed, fertility is low during lactation. The average length of postpartum amenorrhoea is longer when certain breastfeeding practices are followed; this may be done intentionally as birth control (lactational amenorrhea method). Evolution All placental mammals have a uterine lining that builds up when the animal is fertile, but is dismantled (menstruated) when the animal is infertile. Some anthropologists have questioned the energy cost of rebuilding the endometrium every fertility cycle. However, anthropologist Beverly Strassmann has proposed that the energy savings of not having to continuously maintain the uterine lining more than offsets energy cost of having to rebuild the lining in the next fertility cycle, even in species such as humans where much of the lining is lost through bleeding (overt menstruation) rather than reabsorbed (covert menstruation).[1][4] However, even in humans, much of it is reabsorbed. Many have questioned the evolution of overt menstruation in humans and related species, speculating on what advantage there could be to losing blood associated with dismantling the endometrium rather than absorbing it, as most mammals do. The ancient writer Hippocrates considered that menstruation was intended to cleanse the body of "evil humours", and modern evolutionary biologist Margie Profet contends that the primary function of menstruation is to remove sperm-borne pathogens from the uterus. In support of this hypothesis, she has pointed to the relatively high levels of macrophages in menstrual blood.[5][4] Beginning in 1971, some research suggested that menstrual cycles of co-habiting human females became synchronized. A few anthropologists hypothesized that in hunter-gatherer societies, males would go on hunting journeys whilst the females of the tribe were menstruating, speculating that the females would not have been as receptive to sexual relations while menstruating.[6][7] However, there is currently significant dispute as to whether menstrual synchrony exists.[8] Humans do, in fact, reabsorb about two-thirds of the endometrium each cycle. Strassmann asserts that overt menstruation occurs not because it is beneficial in itself. Rather, the fetal development of these species requires a more developed endometrium, one which is too thick to completely reabsorb. Strassman correlates species that have overt menstruation to those that have a large uterus relative to the adult female body size.[1] Culture and menstruation Main article: Culture and menstruation Common usage refers to menstruation and menses as a period. Aside from its biological purpose, this bleeding serves as a sign that a woman has not become pregnant. (However, this cannot be taken as certainty, as sometimes there is some bleeding in early pregnancy, and some women have irregular cycles.) During the reproductive years, failure to

menstruate may provide the first indication to a woman that she may have become pregnant. A woman might say that her "period is late" when an expected menstruation has not started and she might have become pregnant. Many religions have menstruation-related traditions. These may be bans on certain actions during menstruation (such as intercourse in orthodox Judaism and Islam), or rituals to be performed at the end of each menses (such as the mikvah in Judaism and the ghusl in Islam). Some traditional societies sequester females in residences ("menstrual huts") that are reserved for that exclusive purpose until the end of their menstrual period. Since the late 1960s, some women have chosen to prevent menstruation with long-acting hormonal birth control. Injections such as depo-provera became available in the 1960s, progestogen implants such as Norplant in the 1980s and extended cycle combined oral contraceptive pills in the early 2000s. Characteristics Physical experience See also: Premenstrual Syndrome In many women, various intense sensations brought about by the involved hormones and by cramping of the uterus can precede or accompany menstruation. Stronger sensations may include significant menstrual pain (dysmenorrhea), abdominal pain, migraine headaches, depression, emotional sensitivity, feeling bloated, and changes in sex drive. Breast discomfort caused by premenstrual water retention or hormone fluctuation is very common. The sensations experienced vary from woman to woman and from cycle to cycle. Emotional reactions Women may experience emotional disturbances associated with menstruation. These range from the irritability popularly associated with Premenstrual Syndrome (PMS), to tiredness, or "weepiness" (i.e. tears of emotional closeness). A similar range of emotional effects and mood swings is associated with pregnancy.[9] Flow The normal menstrual flow follows a "crescendo-decrescendo" pattern; that is, it starts at a moderate level, increases somewhat, and then slowly tapers. Sudden heavy flows or amounts in excess of 80 mL (hypermenorrhea or menorrhagia) may stem from hormonal disturbance, uterine abnormalities, including uterine leiomyoma or cancer, and other causes. Doctors call the opposite phenomenon, of bleeding very little, hypomenorrhea. Duration The typical woman bleeds for two to seven days at the beginning of each menstrual cycle. Prolonged bleeding (metrorrhagia, also meno-metrorrhagia) no longer shows a clear interval pattern. Dysfunctional uterine bleeding is hormonally caused bleeding abnormalities, typically anovulation. All these bleeding abnormalities need medical attention; they may indicate hormone imbalances, uterine fibroids, or other problems. As pregnant patients may bleed, a pregnancy test forms part of the evaluation of abnormal bleeding. Menstrual products Further information: Menstrual product Most women use something to absorb or catch their menses. There are a number of different methods available. Disposable items: •

Sanitary napkins (Sanitary towels) or pads — Somewhat rectangular pieces of material worn in the

• • •

underwear to absorb menstrual flow, often with "wings," pieces that fold around the panties, and/or an adhesive backing to hold the pad in place. Disposable pads may contain wood pulp or gel products, usually with a plastic lining and bleached. Some sanitary napkins, particularly older styles, are held in place by a beltlike apparatus, instead of adhesive or wings. Tampons — Disposable cylinders of treated rayon/cotton blends or all-cotton fleece, usually bleached, that are inserted into the vagina to absorb menstrual flow. Padettes — Disposable wads of treated rayon/cotton blend fleece that are placed within the inner labia to absorb menstrual flow. Disposable menstrual cups — A firm, flexible cup-shaped device worn inside the vagina to catch menstrual flow. Disposable cups are made of soft plastic.

Reusable items: • • • • •

Reusable cloth pads are made of cotton (often organic), terrycloth, or flannel, and may be handsewn (from material or reused old clothes and towels) or storebought. Menstrual cups — A firm, flexible bell-shaped device worn inside the vagina to catch menstrual flow. Reusable versions include rubber or silicone cups. Sea sponges — Natural sponges, worn internally like a tampon to absorb menstrual flow. Padded panties — Reusable cloth (usually cotton) underwear with extra absorbent layers sewn in to absorb flow. Blanket, towel — (also known as a draw sheet) — large reusable piece of cloth, most often used at night, placed between legs to absorb menstrual flow.

In addition to products to contain the menstrual flow, pharmaceutical companies likewise provide products — commonly non-steroidal anti-inflammatory drugs (NSAIDs) — to relieve menstrual cramps. Some herbs, such as dong quai, raspberry leaf and crampbark, are also claimed to relieve menstrual pain; however there is no documented scientific evidence to prove this..................... From puberty until menopause, a women’s biochemistry waxes and wanes to her own unique monthly rhythm, known as the menstrual cycle. The word menstruation is derived from the Latin word menses, which means month. Regular menstruation is a sign that the body is producing appropriate levels of hormones in a balanced fashion according to a rhythm established over millennia as optimal for human reproduction. Each monthly period results from a sequential conversation between your brain, your adrenal, pituitary and thyroid glands, and your ovaries. This conversation tells your body to release an egg, which is then either fertilized and implanted in the uterus (conception) or shed in your menstrual flow along with the lining of the uterus. The sequence is orchestrated by a cascade of reproductive hormones, but the main actors are estrogen and progesterone. Women generally begin menstruating between the ages of 11 and 13; this first period is called menarche. Most of us will have more than 500 periods during our so-called childbearing years — the time frame between menarche and menopause, which is defined by the point in time when a woman has gone for 12 consecutive months without having a period. When menopause will occur varies for the individual, but the average age is 51. And just as there are gradual changes leading up to menarche, menopause is preceded by a gradual transition phase called perimenopause. Perimenopause is a premenopausal condition often characterized by irregular cycles, sometimes with heavy bleeding or skipped periods (amenorrhea), that can begin as early as the mid- to late-30’s. One thing we’ve learned over the years is that no woman’s menstrual cycle is exactly like any other’s. While some sail through periods without much thought, others suffer with abdominal cramps (dysmenorrhea), excessive bleeding (menorrhagia), moodiness, and more. The range of symptoms that correspond with monthly cycles are sometimes called premenstrual syndrome or PMS, and this time of the month can be extremely difficult to get through for many women......................................... A woman's reproductive years begin in puberty when she starts menstruating and ends when she enters menopause, usually between the age of 45 and 50. While the average length of a menstrual cycle is 28 days, it is perfectly normal for a cycle to last anywhere from 21 to 35 days. On average, most women have menstrual flow for three to five days but it is very normal to menstruate for as much as seven days. Hormones There are five main hormones involved in the menstrual cycle process: estrogen, progesterone, gonadotropin releasing

hormone (GnRH), follicle stimulating hormone (FSH) and lutenizing hormone (LH). Estrogen: Although estrogen is thought of as one type of hormone, there are actually different types of estrogen produced by the female body. The two main estrogens involved in your menstrual cycle are estradiol and androgen. Estradiol is responsible for thickening the endometrial lining along with making your vaginal and cervical mucus more inviting for sperm. Androgen, on the other hand, does not actually start out as estrogen. Rather, the ovaries convert androgen to extra estrogen. This increase in estrogen helps to get rid of the immature egg follicles Progesterone: This hormone is produced by the follicle from which the mature egg has been released (once the egg is released, this follicle is known as the corpus luteum). Progesterone helps make the endometrial lining ready for implantation if an egg is fertilized during the cycle. Progesterone also prevents the egg follicles from developing any further. GnRH: Produced by the hypothalamus in the brain, GnRH is the controlling force behind the production and levels of estrogen in the body. Towards the end of your cycle, your estrogen levels bottom out and the GnRH is notified to start the production all over again. Once your body starts secreting high levels of progesterone, though, GnRH is no longer produced. FSH: Just as the name suggests, increased levels of this hormone help to stimulate egg follicles, thereby aiding the maturation of the eggs as well as increasing the production estradiol. FSH is secreted by the pituitary gland, which is stimulated by the hypothalamus' production of GnRH. LH: Also produced by the pituitary gland in response to your body's production of GnRH. This hormone works with the egg follicles to produce androgen. The First Weeks The first day of your menstrual cycle is the first day of your period. At this time, your estrogen levels are at their lowest which sends a signal to your brain that more FSH is needed. As your body produces more FSH, about 20 egg follicles begin to mature. However, only one of these egg follicles will attract the most FSH and begin to produce estradiol. Once estradiol begins to be secreted, your pituitary gland receives the signal to stop producing FSH in such high volumes. As the production of FSH tapers off, the weaker egg follicles die off. With the increase in estrogen production, your uterine lining begins to thicken while your cervical mucus changes from thick and unwelcoming to sperm to thin and slippery, perfect for sperm to swim in. Not only does the estrogen change the consistency of your cervical mucus, but it also increases the amount of it, which will also help sperm get to your egg. Ovulation Since the beginning of your menstrual cycle, your estrogen levels have been steadily increasing. Approximately 36 hours before you ovulate, these levels will peak and cause the pituitary to release a surge of lutenizing hormone. When the follicle releases the egg, the fimbraie of the fallopian tubes (20 to 25 finger-like structures on the end of the fallopian tubes) collect the egg into the tube where it begins traveling down towards the uterus. This is known as ovulation. Once ovulation occurs, the follicle from which the egg was released shrinks and begins to gather lipids, a type of fatty substance. This follicle then becomes known as the corpus luteum and begins to produce progesterone. As the corpus luteum secretes more and more progesterone, your uterine lining begins to get ready for implantation by a fertilized egg. Once released, the egg is thought to have a 24-hour window during which time it can be fertilized by sperm. However, sperm can survive within the female body anywhere from three to seven days. Women who are looking to avoid a pregnancy should not have sex or should use a reliable form of birth control in the week leading up to ovulation. Menstruation If an egg is fertilized and successfully implants into your uterine lining during this cycle, your body will begin to secrete human Chorionic Gonadotropin (hCG). This hormone helps to continue the production of estrogen and progesterone for the remainder of your pregnancy. The corpus luteum will also continue to produce progesterone as it is stimulated by the fetus' placenta. If an egg is not fertilized, it will be expelled along with the endometrial lining from your body. This is your period. Menstruation will also occur if an egg has been fertilized but fails to implant in the uterine lining. In this case, the fertilized egg along with the endometrium will be expelled during your period. Additionally, when no pregnancy

occurs during a cycle, the corpus luteum dries up, becoming scar tissue, and your hormonal levels begin to fall. As they drop, the hypothalamus will be stimulated and start producing GnRH. This will signal the pituitary gland to start secreting FSH -- and so your menstrual cycle begins again....