Menstrual cycle: Difference between revisions

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Undid edit by Altg20April2nd (talk)There are many more recent peer-reviewed references that state 28 days. And who cares about the moon?! Please discuss in talk page.
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The luteal phase of the menstrual cycle is about the same length in most individuals (mean 14/13 days, SD 1.41 days)<ref name=Lenton_luteal>{{cite journal |author=Lenton EA, Landgren BM, Sexton L |title=Normal variation in the length of the luteal phase of the menstrual cycle: identification of the short luteal phase |journal=Br J Obstet Gynaecol |volume=91 |issue=7 |pages=685–9 |year=1984 |month=July |pmid=6743610}}</ref> whereas the follicular phase tends to show much more variability (log-normally distributed with 95% of individuals having follicular phases between 10.3 and 16.3 days).<ref name=Lenton_follicular>{{cite journal |author=Lenton EA, Landgren BM, Sexton L, Harper R |title=Normal variation in the length of the follicular phase of the menstrual cycle: effect of chronological age |journal=Br J Obstet Gynaecol |volume=91 |issue=7 |pages=681–4 |year=1984 |month=July |pmid=6743609}}</ref> The follicular phase also seems to get significantly shorter with age (geometric mean 14.2 days in women age 18-24 vs. 10.4 days in women aged 40–44).<ref name=Lenton_follicular />
The luteal phase of the menstrual cycle is about the same length in most individuals (mean 14/13 days, SD 1.41 days)<ref name=Lenton_luteal>{{cite journal |author=Lenton EA, Landgren BM, Sexton L |title=Normal variation in the length of the luteal phase of the menstrual cycle: identification of the short luteal phase |journal=Br J Obstet Gynaecol |volume=91 |issue=7 |pages=685–9 |year=1984 |month=July |pmid=6743610}}</ref> whereas the follicular phase tends to show much more variability (log-normally distributed with 95% of individuals having follicular phases between 10.3 and 16.3 days).<ref name=Lenton_follicular>{{cite journal |author=Lenton EA, Landgren BM, Sexton L, Harper R |title=Normal variation in the length of the follicular phase of the menstrual cycle: effect of chronological age |journal=Br J Obstet Gynaecol |volume=91 |issue=7 |pages=681–4 |year=1984 |month=July |pmid=6743609}}</ref> The follicular phase also seems to get significantly shorter with age (geometric mean 14.2 days in women age 18-24 vs. 10.4 days in women aged 40–44).<ref name=Lenton_follicular />

A 1979 study of 305 women found that approximately one-third of the subjects had lunar period cycles in length, i.e.,&nbsp;a mean cycle length of 29.5 days plus or minus 1 day. Almost two-thirds of the subjects started their cycle in the brighter half of the lunar cycle, significantly more than would be expected by random distribution.<ref>{{cite journal |author=Friedmann E |title=Menstrual and lunar cycles |journal=Am. J. Obstet. Gynecol. |volume=140 |issue=3 |pages=350 |year=1981 |month=June |pmid=7246643}}</ref> Another study found a statistically significant number of menstruations occurred around the new moon.<ref>{{cite journal |author=Law SP |title=The regulation of menstrual cycle and its relationship to the moon |journal=Acta Obstet Gynecol Scand |volume=65 |issue=1 |pages=45–8 |year=1986 |pmid=3716780 |doi=10.3109/00016348609158228}}</ref>


== Fertile window ==
== Fertile window ==

Revision as of 21:51, 4 July 2013

See also: Menstruation and Menstruation (mammal)

Menstrual cycle is the cycle of changes that occurs in the uterus and ovary for the purpose of sexual reproduction.[1][2] It is essential for the production of eggs and for the preparation of the uterus for pregnancy.[1] The menstrual cycle occurs only in fertile female humans and other female primates.

In humans, the menstrual cycle is a monthly cycle that averages 28 days per cycle. Each cycle can be divided into three phases based on events in the ovary (ovarian cycle) or in the uterus (uterine cycle).[1] 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 using hormonal contraception to prevent reproduction.[3]

By convention, menstrual cycles are counted from the first day of menstrual bleeding. Stimulated by gradually increasing amounts of estrogen in the follicular phase, discharges of blood (menses) slow then stop, and the lining of the uterus thickens. Follicles in the ovary begin developing under the influence of a complex interplay of hormones, and after several days one or occasionally two become dominant (non-dominant follicles atrophy and die). Approximately mid-cycle, 24–36 hours after the Luteinizing Hormone (LH) surges, the dominant follicle releases an ovum, or egg in an event called ovulation. After ovulation, the egg only lives for 24 hours or less without fertilization while the remains of the dominant follicle in the ovary become a corpus luteum; this body has a primary function of producing large amounts of progesterone. Under the influence of progesterone, the endometrium (uterine lining) changes to prepare for potential implantation of an embryo to establish a pregnancy. If implantation does not occur within approximately two weeks, the corpus luteum will involute, causing sharp drops in levels of both progesterone and estrogen. These hormone drops cause the uterus to shed its lining and egg in a process termed menstruation.

In the menstrual cycle, changes occur in the female reproductive system as well as other systems (which lead to breast tenderness or mood changes, for example). A woman's first menstruation is termed menarche, and occurs typically around age 12-13. The end of a woman's reproductive phase is called the menopause, which commonly occurs somewhere between the ages of 45 and 55.

Overview

The average age of menarche in humans is 12–13 years, but is normal anywhere between ages 8 and 16. The average age of menarche is about 12.5 years in the United States,[4] 12.72 in Canada,[5] 12.9 in the UK[6] and 13.06 ± 0.10 years in Iceland.[7] Factors such as heredity, diet and overall health can accelerate or delay menarche.[8] The cessation of menstrual cycles at the end of a woman's reproductive period is termed menopause. The average age of menopause in women is 52 years, with anywhere between 45 and 55 being common. Menopause before age 45 is considered premature in industrialised countries.[9] Like the age of menarche, the age of menopause is largely a result of cultural and biological factors;[10] however, illnesses, certain surgeries, or medical treatments may cause menopause to occur earlier than it might have otherwise.[11]

The length of a woman's menstrual cycle will typically vary, with some shorter cycles and some longer cycles. A woman who experiences variations of less than eight days between her longest cycles and shortest cycles is considered to have regular menstrual cycles. It is unusual for a woman to experience cycle length variations of less than four days. Length variation between eight and 20 days is considered as moderately irregular cycles. Variation of 21 days or more between a woman's shortest and longest cycle lengths is considered very irregular. [12]

Cycles and phases

Menstrual cycle

The menstrual cycle can be described by the ovarian or uterine cycle. The ovarian cycle describes changes that occur in the follicles of the ovary whereas the uterine cycle describes changes in the endometrial lining of the uterus. Both cycles can be divided into three phases. The ovarian cycle consists of the follicular phase, ovulation, and the luteal phase whereas the uterine cycle consists of menstruation, proliferative phase, and secretory phase.[1]

Ovarian cycle

Follicular phase

Main article: Follicular phase

The follicular phase is the first part of the ovarian cycle. During this phase, the ovarian follicles mature and ready to release an egg.[1] The latter part of this phase overlaps with the proliferative phase of the uterine cycle.

Through the influence of a rise in follicle stimulating hormone (FSH) during the first days of the cycle, a few ovarian follicles are stimulated.[13] These follicles, which were present at birth[13] and have been developing for the better part of a year in a process known as folliculogenesis, compete with each other for dominance. Under the influence of several hormones, all but one of these follicles will stop growing, while one dominant follicle in the ovary will continue to maturity. The follicle that reaches maturity is called a tertiary, or Graafian, follicle, and it contains the ovum.[13]

Ovulation

Main article: Ovulation
An ovary about to release an egg.

Ovulation is the second phase of the ovarian cycle in which a mature egg is released from the ovarian follicles into the oviduct.[14] During the follicular phase, estradiol suppresses production of luteinizing hormone (LH) from the anterior pituitary gland. When the egg has nearly matured, levels of estradiol reach a threshold above which this effect is reversed and estrogen actually stimulates the production of a large amount of LH. This process, known as the LH surge, starts around day 12 of the average cycle and may last 48 hours.[citation needed]

The exact mechanism of these opposite responses of LH levels to estradiol is not well understood.[15]:86 In animals, a Gonadotropin-releasing hormone (GnRH) surge has been shown to precede the LH surge, suggesting that estrogen's main effect is on the hypothalamus, which controls GnRH secretion.[15]:86 This may be enabled by the presence of two different estrogen receptors in the hypothalamus: estrogen receptor alpha, which is responsible for the negative feedback estradiol-LH loop, and estrogen receptor beta, which is responsible for the positive estradiol-LH relationship.[16] However in humans it has been shown that high levels of estradiol can provoke abrupt increases in LH, even when GnRH levels and pulse frequencies are held constant,[15]:86 suggesting that estrogen acts directly on the pituitary to provoke the LH surge.

The release of LH matures the egg and weakens the wall of the follicle in the ovary, causing the fully developed follicle to release its secondary oocyte.[13] The secondary oocyte promptly matures into an ootid and then becomes a mature ovum. The mature ovum has a diameter of about 0.2 mm.[17]

Which of the two ovaries—left or right—ovulates appears essentially random; no known left and right co-ordination exists.[18] Occasionally, both ovaries will release an egg;[18] if both eggs are fertilized, the result is fraternal twins.[19]

After being released from the ovary, the egg is swept into the fallopian tube by the fimbria, which is a fringe of tissue at the end of each fallopian tube. After about a day, an unfertilized egg will disintegrate or dissolve in the fallopian tube.[13]

Fertilization by a spermatozoon, when it occurs, usually takes place in the ampulla, the widest section of the fallopian tubes. A fertilized egg immediately begins the process of embryogenesis, or development. The developing embryo takes about three days to reach the uterus and another three days to implant into the endometrium.[13] It has usually reached the blastocyst stage at the time of implantation.

In some women, ovulation features a characteristic pain called mittelschmerz (German term meaning middle pain).[20] The sudden change in hormones at the time of ovulation sometimes also causes light mid-cycle blood flow.[21]

Luteal phase

Main article: Luteal phase

The luteal phase is the final phase of the ovarian cycle and it corresponds to the secretory phase of the uterine cycle. During the luteal phase, the pituitary hormones FSH and LH cause the remaining parts of the dominant follicle to transform into the corpus luteum, which produces progesterone. The increased progesterone in the adrenals starts to induce the production of estrogen. The hormones produced by the corpus luteum also suppress production of the FSH and LH that the corpus luteum needs to maintain itself. Consequently, the level of FSH and LH fall quickly over time, and the corpus luteum subsequently atrophies.[13] Falling levels of progesterone trigger menstruation and the beginning of the next cycle. From the time of ovulation until progesterone withdrawal has caused menstruation to begin, the process typically takes about two weeks, with 14 days considered normal. For an individual woman, the follicular phase often varies in length from cycle to cycle; by contrast, the length of her luteal phase will be fairly consistent from cycle to cycle.[22]

The loss of the corpus luteum can be prevented by fertilization of the egg; the resulting embryo produces human chorionic gonadotropin (hCG), which is very similar to LH and which can preserve the corpus luteum. Because the hormone is unique to the embryo, most pregnancy tests look for the presence of hCG.[13]

Uterine cycle

Menstruation

Main article: Menstruation

Menstruation (also called menstrual bleeding, menses, catamenia or a period) is the first phase of the uterine cycle. The flow of menses normally serves as a sign that a woman has not become pregnant. (However, this cannot be taken as certainty, as a number of factors can cause bleeding during pregnancy; some factors are specific to early pregnancy, and some can cause heavy flow.)[23][24][25]

Levels of estradiol (the main estrogen), progesterone, luteinizing hormone, and follicle-stimulating hormone during the menstrual cycle, taking inter-cycle and inter-woman variability into account.[26]

Eumenorrhea denotes normal, regular menstruation that lasts for a few days (usually 3 to 5 days, but anywhere from 2 to 7 days is considered normal).[27][20] The average blood loss during menstruation is 35 milliliters with 10–80 ml considered normal.[28] Women who experience Menorrhagia are more susceptible to iron deficiency than the average person.[29] An enzyme called plasmin inhibits clotting in the menstrual fluid.[30]

Painful cramping in the abdomen, back, or upper thighs is common during the first few days of menstruation. Severe uterine pain during menstruation is known as dysmenorrhea, and it is most common among adolescents and younger women (affecting about 67.2% of adolescent females).[31] When menstruation begins, symptoms of premenstrual syndrome (PMS) such as breast tenderness and irritability generally decrease.[20] Many sanitary products are marketed to women for use during their menstruation.

Proliferative phase

The proliferative phase is the second phase of the uterine cycle when a hormone causes the lining of the uterus to grow, or proliferate, during this time.[13] As they mature, the ovarian follicles secrete increasing amounts of estradiol, an estrogen. The estrogens initiate the formation of a new layer of endometrium in the uterus, histologically identified as the proliferative endometrium. The estrogen also stimulates crypts in the cervix to produce fertile cervical mucus, which may be noticed by women practicing fertility awareness.[32]

Secretory phase

The secretory phase is the final phase of the uterine cycle and it corresponds to the luteal phase of the ovarian cycle. During the secretory phase, the corpus luteum produces progesterone, which plays a vital role in making the endometrium receptive to implantation of the blastocyst and supportive of the early pregnancy, by increasing blood flow and uterine secretions and reducing the contractility of the smooth muscle in the uterus;[33] it also has the side effect of raising the woman's basal body temperature.[34]

Length

The average menstrual cycle lasts 28 days. The variability of menstrual cycle lengths is highest for women under 25 years of age and is lowest, that is, most regular, for ages 35 to 39.[35] Subsequently, the variability increases slightly for women aged 40 to 44.[35] Usually, length variation between eight and 20 days in a woman is considered as moderately irregular menstrual cycles.[12] Variation of 21 days or more is considered very irregular.[12]

As measured on women undergoing in vitro fertilization, a longer menstrual cycle length is associated with higher pregnancy and delivery rates, even after age adjustment.[36] Delivery rates after IVF have been estimated to be almost doubled for women with a menstrual cycle length of more than 34 days compared with women with a menstrual cycle length shorter than 26 days.[36] A longer menstrual cycle length is also significantly associated with better ovarian response to gonadotropin stimulation and embryo quality.[36]

The luteal phase of the menstrual cycle is about the same length in most individuals (mean 14/13 days, SD 1.41 days)[37] whereas the follicular phase tends to show much more variability (log-normally distributed with 95% of individuals having follicular phases between 10.3 and 16.3 days).[38] The follicular phase also seems to get significantly shorter with age (geometric mean 14.2 days in women age 18-24 vs. 10.4 days in women aged 40–44).[38]

Fertile window

Main article: Fertility testing

The most fertile period (the time with the highest likelihood of pregnancy resulting from sexual intercourse) covers the time from some 5 days before until 1 to 2 days after ovulation.[39] In a 28‑day cycle with a 14‑day luteal phase, this corresponds to the second and the beginning of the third week. A variety of methods have been developed to help individual women estimate the relatively fertile and the relatively infertile days in the cycle; these systems are called fertility awareness.

Fertility awareness methods that rely on cycle length records alone are called calendar-based methods.[40] Methods that require observation of one or more of the three primary fertility signs (basal body temperature, cervical mucus, and cervical position)[41] are known as symptoms-based methods.[40] Urine test kits are available that detect the LH surge that occurs 24 to 36 hours before ovulation; these are known as ovulation predictor kits (OPKs).[42] Computerized devices that interpret basal body temperatures, urinary test results, or changes in saliva are called fertility monitors.

A woman's fertility is also affected by her age.[43] As a woman's total egg supply is formed in fetal life,[44] to be ovulated decades later, it has been suggested that this long lifetime may make the chromatin of eggs more vulnerable to division problems, breakage, and mutation than the chromatin of sperm, which are produced continuously during a man's reproductive life. However, despite this hypothesis, a similar paternal age effect has also been observed.

Effect on other systems

Some women with neurological conditions experience increased activity of their conditions at about the same time during each menstrual cycle. For example, drops in estrogen levels have been known to trigger migraines,[45] especially when the woman who suffers migraines is also taking the birth control pill. Many women with epilepsy have more seizures in a pattern linked to the menstrual cycle; this is called "catamenial epilepsy".[46] Different patterns seem to exist (such as seizures coinciding with the time of menstruation, or coinciding with the time of ovulation), and the frequency with which they occur has not been firmly established. Using one particular definition, one group of scientists found that around one-third of women with intractable partial epilepsy have catamenial epilepsy.[46][47][48] An effect of hormones has been proposed, in which progesterone declines and estrogen increases would trigger seizures.[49] Recently, studies have shown that high doses of estrogen can cause or worsen seizures, whereas high doses of progestrone can act like an antiepileptic drug.[50] Studies by medical journals have found that women experiencing menses are 1.68 times more likely to commit suicide.[51]

Mice have been used as an experimental system to investigate possible mechanisms by which levels of sex steroid hormones might regulate nervous system function. During the part of the mouse estrous cycle when progesterone is highest, the level of nerve-cell GABA receptor subtype delta was high. Since these GABA receptors are inhibitory, nerve cells with more delta receptors are less likely to fire than cells with lower numbers of delta receptors. During the part of the mouse estrous cycle when estrogen levels are higher than progesterone levels, the number of delta receptors decrease, increasing nerve cell activity, in turn increasing anxiety and seizure susceptibility.[52]

Estrogen levels may affect thyroid behavior.[53] For example, during the luteal phase (when estrogen levels are lower), the velocity of blood flow in the thyroid is lower than during the follicular phase (when estrogen levels are higher).[54]

Among women living closely together, it was once thought that the onsets of menstruation tend to synchronize. This effect was first described in 1971, and possibly explained by the action of pheromones in 1998.[55] Subsequent research has called this hypothesis into question.[56]

Research indicates that women have a significantly higher likelihood of anterior cruciate ligament injuries in the pre-ovulatory stage, than post-ovulatory stage.[57]

Mood and behavior

The different phases of the menstrual cycle correlate with women’s moods. In some cases, hormones released during the menstrual cycle can cause behavioral changes in females; mild to severe mood swings can occur.[58]The menstrual cycle phase and ovarian hormones may contribute to increased empathy in women. The natural shift of hormone levels during the different phases of the menstrual cycle have been studied in conjunction with test scores. When completing empathy exercises, women in the follicular stage of their menstrual cycle performed better than women in their midluteal phase. A significant correlation between progesterone levels and the ability to accurately recognize emotion was found. Performances on emotion recognition tasks were better when women had lower progesterone levels. Women in the follicular stage showed higher emotion recognition accuracy then their midluteal phase counterparts. Women were found to react more to negative stimuli when in midluteal stage over the women in the follicular stage, perhaps indicating more reactivity to social stress during that menstrual cycle phase.[59] Overall, it has been found that women in the follicular phase demonstrated better performance in tasks that contain empathetic traits.

Fear response in women during two different points in the menstrual cycle has been examined. When oestrogen is highest in the preovulatory stage, women are significantly better at identifying expressions of fear than women who were menstruating which is when oestrogen levels are lowest. The women were equally able to identify happy faces, demonstrating that the fear response was a more powerful response. To summarize, menstrual cycle phase and the oestrogen levels correlates with women’s fear processing.[60]

However, the examination of daily moods in women with measuring ovarian hormones may indicate a less powerful connection. In comparison to levels of stress or physical health, the ovarian hormones had less of an impact on overall mood.[61] This indicates that while changes of ovarian hormones may influence mood, on a day-to-day level it does not influence mood more than other stressors do.

Cycle abnormalities and disorders

Main article: Menstrual disorder

Infrequent or irregular ovulation is called oligoovulation.[62] The absence of ovulation is called anovulation. Normal menstrual flow can occur without ovulation preceding it: an anovulatory cycle. In some cycles, follicular development may start but not be completed; nevertheless, estrogens will be formed and stimulate the uterine lining. Anovulatory flow resulting from a very thick endometrium caused by prolonged, continued high estrogen levels is called estrogen breakthrough bleeding. Anovulatory bleeding triggered by a sudden drop in estrogen levels is called changes.[63] Anovulatory cycles commonly occur before menopause (perimenopause) and in women with polycystic ovary syndrome.[64]

Very little flow (less than 10 ml) is called hypomenorrhea. Regular cycles with intervals of 21 days or fewer are polymenorrhea; frequent but irregular menstruation is known as metrorrhagia. Sudden heavy flows or amounts greater than 80 ml are termed menorrhagia.[65] Heavy menstruation that occurs frequently and irregularly is menometrorrhagia. The term for cycles with intervals exceeding 35 days is oligomenorrhea.[66] Amenorrhea refers to more than three[65] to six[66] months without menses (while not being pregnant) during a woman's reproductive years.

George Preti, an organic chemist at the Monell Chemical Senses Center in Philadelphia and Winnefred Cutler of the University of Pennsylvania's psychology department, discovered that women with irregular menstrual cycles became regular when exposed to male underarm extracts.[67] They hypothesized that the only explanation was that underarms contain pheromones, as there was no other explanation for the effects, which mirrored how pheromones affect other mammals.[67]

Ovulation suppression

Hormonal contraception

Main article: Hormonal contraception
Half-used blister pack of a combined oral contraceptive. The white pills are placebos, mainly for the purpose of reminding the woman to continue taking the pills.

While some forms of birth control do not affect the menstrual cycle, hormonal contraceptives work by disrupting it. Progestogen negative feedback decreases the pulse frequency of gonadotropin-releasing hormone (GnRH) release by the hypothalamus, which decreases the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) by the anterior pituitary. Decreased levels of FSH inhibit follicular development, preventing an increase in estradiol levels. Progestogen negative feedback and the lack of estrogen positive feedback on LH release prevent a mid-cycle LH surge. Inhibition of follicular development and the absence of a LH surge prevent ovulation.[68][69][70]

The degree of ovulation suppression in progestogen-only contraceptives depends on the progestogen activity and dose. Low dose progestogen-only contraceptives—traditional progestogen only pills, subdermal implants Norplant and Jadelle, and intrauterine system Mirena—inhibit ovulation in about 50% of cycles and rely mainly on other effects, such as thickening of cervical mucus, for their contraceptive effectiveness.[71] Intermediate dose progestogen-only contraceptives—the progestogen-only pill Cerazette and the subdermal implant Nexplanon—allow some follicular development but more consistently inhibit ovulation in 97–99% of cycles. The same cervical mucus changes occur as with very low-dose progestogens. High-dose, progestogen-only contraceptives—the injectables Depo-Provera and Noristerat—completely inhibit follicular development and ovulation.[71]

Combined hormonal contraceptives include both an estrogen and a progestogen. Estrogen negative feedback on the anterior pituitary greatly decreases the release of LH, which makes combined hormonal contraceptives more effective at inhibiting follicular development and preventing ovulation. Estrogen also reduces the incidence of irregular breakthrough bleeding.[68][69][70] Several combined hormonal contraceptives—the pill, NuvaRing, and the contraceptive patch—are usually used in a way that causes regular withdrawal bleeding. In a normal cycle, menstruation occurs when estrogen and progesterone levels drop rapidly.[34] Temporarily discontinuing use of combined hormonal contraceptives (a placebo week, not using patch or ring for a week) has a similar effect of causing the uterine lining to shed. If withdrawal bleeding is not desired, combined hormonal contraceptives may be taken continuously, although this increases the risk of breakthrough bleeding.

Lactational amenorrhea

Main article: Lactational amenorrhea method

Breastfeeding causes negative feedback to occur on pulse secretion of gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH). Depending on the strength of the negative feedback, breastfeeding women may experience complete suppression of follicular development, follicular development but no ovulation, or normal menstrual cycles may resume.[72] Suppression of ovulation is more likely when suckling occurs more frequently.[73] The production of prolactin in response to suckling is important to maintaining lactational amenorrhea.[74] On average, women who are fully breastfeeding whose infants suckle frequently experience a return of menstruation at fourteen and a half months postpartum. There is a wide range of response among individual breastfeeding women, however, with some experiencing return of menstruation at two months and others remaining amenorrheic for up to 42 months postpartum.[75]

Etymological and biological associations

Nightlighting and the moon

See also: Culture and menstruation and Lunar effect

The word "menstruation" is etymologically related to "moon". The terms "menstruation" and "menses" are derived from the Latin mensis (month), which in turn relates to the Greek mene (moon) and to the roots of the English words month and moon.[76]

Some authors believe that, historically, women in traditional societies without nightlighting ovulated with the full moon and menstruated with the new moon,[77] and one author documents the controversial attempts to use the association to improve the rhythm method of regulating conception.[76][78]

Some studies in both humans[79] and other animals[80] have found that artificial light at night does influence the menstrual cycle in humans and the estrus cycle in mice (cycles are more regular in the absence of artificial light at night). It has also been suggested that bright light exposure in the morning promotes more regular cycles.[81] One author has suggested that sensitivity of women's cycles to nightlighting is caused by nutritional deficiencies of certain vitamins and minerals.[82]

A meta-analysis of studies from 1996 showed no correlation between the human menstrual cycle and the lunar cycle.[83][84][85][86][87][88] Dogon villagers did not have electric lighting and spent most nights outdoors, talking and sleeping; so they were an ideal population for detecting a lunar influence; none, however, was found.[89]

References

  1. ^ a b c d e Silverthorn, Dee Unglaub (2013). Human Physiology: An Integrated Approach (6th ed.). Glenview, IL: Pearson Education, Inc. pp. 850–890. ISBN 0-321-75007-1.
  2. ^ Sherwood, Laurelee (2013). Human Physiology: From Cells to Systems (8th ed.). Belmont, CA: Cengage. pp. 735–794. ISBN 1-111-57743-9.
  3. ^ Klump KL, Keel PK, Racine SE; et al. (2013). "The interactive effects of estrogen and progesterone on changes in emotional eating across the menstrual cycle". J Abnorm Psychol. 122 (1): 131–7. doi:10.1037/a0029524. PMID 22889242. {{cite journal}}: Explicit use of et al. in: |author= (help); Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  4. ^ Anderson SE, Dallal GE, Must A (2003). "Relative weight and race influence average age at menarche: results from two nationally representative surveys of US girls studied 25 years apart". Pediatrics. 111 (4 Pt 1): 844–50. doi:10.1542/peds.111.4.844. PMID 12671122. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  5. ^ Al-Sahab B, Ardern CI, Hamadeh MJ, Tamim H (2010). "Age at menarche in Canada: results from the National Longitudinal Survey of Children & Youth". BMC Public Health. 10: 736. doi:10.1186/1471-2458-10-736. PMC 3001737. PMID 21110899.{{cite journal}}: CS1 maint: multiple names: authors list (link) CS1 maint: unflagged free DOI (link)
  6. ^ http://vstudentworld.yolasite.com/resources/final_yr/gynae_obs/Hamilton%20Fairley%20Obstetrics%20and%20Gynaecology%20Lecture%20Notes%202%20Ed.pdf[full citation needed]
  7. ^ Macgússon TE (1978). "Age at menarche in Iceland". Am. J. Phys. Anthropol. 48 (4): 511–4. doi:10.1002/ajpa.1330480410. PMID 655271. {{cite journal}}: Unknown parameter |month= ignored (help)
  8. ^ "At what age does a girl get her first period?". National Women's Health Information Center. Retrieved 2011-11-20.
  9. ^ "Clinical topic - Menopause". NHS. Retrieved 2 November 2009.
  10. ^ Beyene, Yewoubdar (1989). From Menarche to Menopause: Reproductive Lives of Peasant Women in Two Cultures. Albany, NY: State University of New York Press. ISBN 0-88706-866-9.
  11. ^ Shuman, Tracy (2006). "Your Guide to Menopause". WebMD. Retrieved 16 December 2006. {{cite web}}: Unknown parameter |month= ignored (help)
  12. ^ a b c Kippley, John; Kippley, Sheila (1996). The Art of Natural Family Planning (4th ed.). Cincinnati: The Couple to Couple League. p. 92. ISBN 978-0-926412-13-2.
  13. ^ a b c d e f g h i Losos, Jonathan B.; Raven, Peter H.; Johnson, George B.; Singer, Susan R. (2002). Biology. New York: McGraw-Hill. pp. 1207–09. ISBN 0-07-303120-8.
  14. ^ Ovulation Test at Duke Fertility Center. Retrieved July 2, 2011
  15. ^ a b c Lentz, Gretchen M (2013). Comprehensive gynecology. St. Louis: Elsevier Mosby. ISBN 978-0-323-06986-1. Retrieved 5 April 2012. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  16. ^ Hu L, Gustofson RL, Feng H; et al. (2008). "Converse regulatory functions of estrogen receptor-alpha and -beta subtypes expressed in hypothalamic gonadotropin-releasing hormone neurons". Mol. Endocrinol. 22 (10): 2250–9. doi:10.1210/me.2008-0192. PMC 2582533. PMID 18701637. {{cite journal}}: Explicit use of et al. in: |author= (help); Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  17. ^ Gray, Henry David (2000). "The Ovum". Anatomy of the human body. Philadelphia: Bartleby.com. ISBN 1-58734-102-6. {{cite book}}: |access-date= requires |url= (help); External link in |chapterurl= (help); Unknown parameter |chapterurl= ignored (|chapter-url= suggested) (help)
  18. ^ a b Ecochard R, Gougeon A (2000). "Side of ovulation and cycle characteristics in normally fertile women". Hum. Reprod. 15 (4): 752–5. doi:10.1093/humrep/15.4.752. PMID 10739814. {{cite journal}}: Unknown parameter |month= ignored (help)
  19. ^ "Multiple Pregnancy: Twins or More - Topic Overview". WebMD Medical Reference from Healthwise. 24 July 2007. Retrieved 5 October 2008.
  20. ^ a b c John M Goldenring (1 February 2007). "All About Menstruation". WebMD. Retrieved 5 October 2008.
  21. ^ Weschler (2002), p.65
  22. ^ Weschler (2002), p.47
  23. ^ Greenfield, Marjorie (17 September 2001). "Subchorionic Hematoma in Early Pregnancy". Ask Our Experts. DrSpock.com. Archived from the original on 15 September 2008. Retrieved 21 September 2008.
  24. ^ Anderson-Berry, Ann L (10 December 2007). "Vanishing Twin Syndrome". Emedicine.com. WebMD. Retrieved 21 September 2008. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  25. ^ Ko, Patrick (23 August 2007). "Placenta Previa". Emedicine.com. WebMD. Retrieved 21 September 2008. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  26. ^ References and further description of values are given in image page in Wikimedia Commons at Commons:File:Hormones estradiol, progesterone, LH and FSH during menstrual cycle.svg.
  27. ^ "Menstruation and the Menstrual Cycle". Womenshealth.gov. April 2007. Archived from the original on 24 Oct 2008.
  28. ^ David L Healy (2004-11-24). "Menorrhagia Heavy Periods - Current Issues". Monash University. ABN 12 377 614 012.
  29. ^ Harvey LJ, Armah CN, Dainty JR; et al. (2005). "Impact of menstrual blood loss and diet on iron deficiency among women in the UK". Br. J. Nutr. 94 (4): 557–64. doi:10.1079/BJN20051493. PMID 16197581. {{cite journal}}: Explicit use of et al. in: |author= (help); Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  30. ^ Shiraishi M (1962). "Studies on identification of menstrual blood stain by fibrin-plate method. I. A study on the incoagulability of menstrual blood". Acta Med Okayama. 16: 192–200. PMID 13977381. {{cite journal}}: Unknown parameter |month= ignored (help)
  31. ^ Sharma P, Malhotra C, Taneja DK, Saha R (2008). "Problems related to menstruation amongst adolescent girls". Indian J Pediatr. 75 (2): 125–9. doi:10.1007/s12098-008-0018-5. PMID 18334791. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  32. ^ Weschler, Toni (2002). Taking Charge of Your Fertility (Revised ed.). New York: HarperCollins. pp. 359–361. ISBN 0-06-093764-5.
  33. ^ Lombardi, Julian (1998). Comparative Vertebrate Reproduction. Springer. p. 184. ISBN 9780792383369.
  34. ^ a b Weschler (2002), pp.361-2
  35. ^ a b Chiazze L, Brayer FT, Macisco JJ, Parker MP, Duffy BJ (1968). "The length and variability of the human menstrual cycle". JAMA. 203 (6): 377–80. doi:10.1001/jama.1968.03140060001001. PMID 5694118. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  36. ^ a b c Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 18155201, please use {{cite journal}} with |pmid=18155201 instead.
  37. ^ Lenton EA, Landgren BM, Sexton L (1984). "Normal variation in the length of the luteal phase of the menstrual cycle: identification of the short luteal phase". Br J Obstet Gynaecol. 91 (7): 685–9. PMID 6743610. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  38. ^ a b Lenton EA, Landgren BM, Sexton L, Harper R (1984). "Normal variation in the length of the follicular phase of the menstrual cycle: effect of chronological age". Br J Obstet Gynaecol. 91 (7): 681–4. PMID 6743609. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  39. ^ Weschler (2002), pp.242,374
  40. ^ a b "Medical Eligibility Criteria for Contraceptive Use:Fertility awareness-based methods". Third edition. World Health Organization. 2004. Retrieved 29 April 2008. {{cite journal}}: Cite journal requires |journal= (help)
  41. ^ Weschler (2002), p.52
  42. ^ MedlinePlus Encyclopedia: LH urine test (home test)
  43. ^ Leridon H (2004). "Can assisted reproduction technology compensate for the natural decline in fertility with age? A model assessment". Hum. Reprod. 19 (7): 1548–53. doi:10.1093/humrep/deh304. PMID 15205397. {{cite journal}}: Unknown parameter |month= ignored (help)
  44. ^ Krock, Lexi (2001). "Fertility Throughout Life". 18 Ways to Make a Baby. NOVA Online. Retrieved 24 December 2006. {{cite web}}: Unknown parameter |month= ignored (help) Haines, Cynthiac (2006). "Your Guide to the Female Reproductive System". The Cleveland Clinic Women's Health Center. WebMD. Retrieved 24 December 2006. {{cite web}}: Unknown parameter |month= ignored (help)
  45. ^ "Migraine and Estrogen Officially Linked". The Daily Headache. Retrieved 2012-10-19.
  46. ^ a b Herzog AG (2008). "Catamenial epilepsy: definition, prevalence pathophysiology and treatment". Seizure. 17 (2): 151–9. doi:10.1016/j.seizure.2007.11.014. PMID 18164632. {{cite journal}}: Unknown parameter |month= ignored (help)
  47. ^ Herzog AG, Harden CL, Liporace J; et al. (2004). "Frequency of catamenial seizure exacerbation in women with localization-related epilepsy". Ann. Neurol. 56 (3): 431–4. doi:10.1002/ana.20214. PMID 15349872. {{cite journal}}: Explicit use of et al. in: |author= (help); Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  48. ^ Herzog AG, Klein P, Ransil BJ (1997). "Three patterns of catamenial epilepsy". Epilepsia. 38 (10): 1082–8. doi:10.1111/j.1528-1157.1997.tb01197.x. PMID 9579954. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  49. ^ Scharfman HE, MacLusky NJ (2006). "The influence of gonadal hormones on neuronal excitability, seizures, and epilepsy in the female". Epilepsia. 47 (9): 1423–40. doi:10.1111/j.1528-1167.2006.00672.x. PMC 1924802. PMID 16981857. {{cite journal}}: Unknown parameter |month= ignored (help)
  50. ^ "Menstrual cycle". epilepsy.com. Retrieved 2012-10-19.
  51. ^ Baca-García E, Diaz-Sastre C, Ceverino A, Saiz-Ruiz J, Diaz FJ, de Leon J (2003). "Association between the menses and suicide attempts: a replication study". Psychosom Med. 65 (2): 237–44. doi:10.1097/01.PSY.0000058375.50240.F6. PMID 12651991.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  52. ^ Maguire JL, Stell BM, Rafizadeh M, Mody I (2005). "Ovarian cycle-linked changes in GABA(A) receptors mediating tonic inhibition alter seizure susceptibility and anxiety". Nat. Neurosci. 8 (6): 797–804. doi:10.1038/nn1469. PMID 15895085. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  53. ^ Doufas AG, Mastorakos G (2000). "The hypothalamic-pituitary-thyroid axis and the female reproductive system". Ann. N. Y. Acad. Sci. 900: 65–76. doi:10.1111/j.1749-6632.2000.tb06217.x. PMID 10818393.
  54. ^ Krejza J, Nowacka A, Szylak A, Bilello M, Melhem LY (2004). "Variability of thyroid blood flow Doppler parameters in healthy women". Ultrasound Med Biol. 30 (7): 867–76. doi:10.1016/j.ultrasmedbio.2004.05.008. PMID 15313319. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  55. ^ Stern K, McClintock MK (1998). "Regulation of ovulation by human pheromones". Nature. 392 (6672): 177–9. doi:10.1038/32408. PMID 9515961. {{cite journal}}: Unknown parameter |month= ignored (help)
  56. ^ Adams, Cecil (20 December 2002). "Does menstrual synchrony really exist?". The Straight Dope. The Chicao Reader. Retrieved 10 January 2007.
  57. ^ Renstrom P, Ljungqvist A, Arendt E; et al. (2008). "Non-contact ACL injuries in female athletes: an International Olympic Committee current concepts statement". Br J Sports Med. 42 (6): 394–412. doi:10.1136/bjsm.2008.048934. PMID 18539658. {{cite journal}}: Explicit use of et al. in: |author= (help); Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  58. ^ Schmidt PJ, Nieman LK, Danaceau MA, Adams LF, Rubinow DR (1998). "Differential behavioral effects of gonadal steroids in women with and in those without premenstrual syndrome". N. Engl. J. Med. 338 (4): 209–16. doi:10.1056/NEJM199801223380401. PMID 9435325. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  59. ^ Derntl B, Hack RL, Kryspin-Exner I, Habel U (2013). "Association of menstrual cycle phase with the core components of empathy". Horm Behav. 63 (1): 97–104. doi:10.1016/j.yhbeh.2012.10.009. PMC 3549494. PMID 23098806. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  60. ^ Schwartz DH, Romans SE, Meiyappan S, De Souza MJ, Einstein G (2012). "The role of ovarian steroid hormones in mood". Horm Behav. 62 (4): 448–54. doi:10.1016/j.yhbeh.2012.08.001. PMID 22902271. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  61. ^ Pearson R, Lewis MB (2005). "Fear recognition across the menstrual cycle". Horm Behav. 47 (3): 267–71. doi:10.1016/j.yhbeh.2004.11.003. PMID 15708754. {{cite journal}}: Unknown parameter |month= ignored (help)
  62. ^ Galan, Nicole (16 April 2008). "Oligoovulation". about.com. Retrieved 12 October 2008.
  63. ^ Weschler (2002), p.107
  64. ^ Anovulation at eMedicine
  65. ^ a b Menstruation Disorders at eMedicine
  66. ^ a b Oriel KA, Schrager S (1999). "Abnormal uterine bleeding". Am Fam Physician. 60 (5): 1371–80, discussion 1381–2. PMID 10524483. {{cite journal}}: Unknown parameter |month= ignored (help)
  67. ^ a b Delude, Cathryn M. (September 2, 2003). "Looking for love potion number nine". Boston Globe.
  68. ^ a b Trussell, James (2007). "Contraceptive Efficacy". In Hatcher, Robert A.; et al. (eds.). Contraceptive Technology (19th rev. ed.). New York: Ardent Media. ISBN 0-9664902-0-7. {{cite book}}: Explicit use of et al. in: |editor= (help); External link in |chapterurl= (help); Unknown parameter |chapterurl= ignored (|chapter-url= suggested) (help)
  69. ^ a b Speroff, Leon; Darney, Philip D. (2005). "Oral Contraception". A Clinical Guide for Contraception (4th ed.). Philadelphia: Lippincott Williams & Wilkins. pp. 21–138. ISBN 0-7817-6488-2.{{cite book}}: CS1 maint: multiple names: authors list (link)
  70. ^ a b Loose, Davis S.; Stancel, George M. (2006). "Estrogens and Progestins". In Brunton, Laurence L.; Lazo, John S.; Parker, Keith L. (eds.) (ed.). Goodman & Gilman's The Pharmacological Basis of Therapeutics (11th ed.). New York: McGraw-Hill. pp. 1541–71. ISBN 0-07-142280-3. {{cite book}}: |editor= has generic name (help)CS1 maint: multiple names: authors list (link)
  71. ^ a b Glasier, Anna (2006). "Contraception". In DeGroot, Leslie J.; Jameson, J. Larry (eds.) (ed.). Endocrinology (5th ed.). Philadelphia: Elsevier Saunders. pp. 3000–1. ISBN 0-7216-0376-9. {{cite book}}: |editor= has generic name (help)CS1 maint: multiple names: editors list (link)
  72. ^ McNeilly AS (2001). "Lactational control of reproduction". Reprod. Fertil. Dev. 13 (7–8): 583–90. doi:10.1071/RD01056. PMID 11999309.
  73. ^ Kippley, John (1996). The Art of Natural Family Planning (4th ed.). Cincinnati, OH: The Couple to Couple League. p. 347. ISBN 0-926412-13-2. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  74. ^ Stallings JF, Worthman CM, Panter-Brick C, Coates RJ (1996). "Prolactin response to suckling and maintenance of postpartum amenorrhea among intensively breastfeeding Nepali women". Endocr. Res. 22 (1): 1–28. doi:10.3109/07435809609030495. PMID 8690004. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  75. ^ "Breastfeeding: Does It Really Space Babies?". The Couple to Couple League International. Internet Archive. 17 January 2008. Archived from the original on 17 January 2008. Retrieved 21 September 2008., which cites:
    Sheila K. and John F. Kippley (November–December 1972). "The relation between breastfeeding and amenorrhea". Journal of obstetric, gynecologic, and neonatal nursing. 1 (4): 15–21. PMID 4485271.
    Sheila Kippley (November–December 1986 and January–February 1987). "Breastfeeding survey results similar to 1971 study". The CCL News. 13 (3): 10. {{cite journal}}: Check date values in: |date= (help) and 13(4): 5.
  76. ^ a b Allen, Kevin (2007). The Reluctant Hypothesis: A History of Discourse Surrounding the Lunar Phase Method of Regulating Conception. Lacuna Press. p. 239. ISBN 978-0-9510974-2-7.
  77. ^ Cohen, Sari (February–March 2005). "Melatonin, menstruation, and the moon". Townsend Letter for Doctors and Patients. Retrieved 21 September 2008.
    Knight, Chris (1995). "The Human Symbolic Revolution: A Darwinian Account" (PDF). Cambridge Archaeological Journal. 5 (1): 75–114. doi:10.1017/S0959774300001190. Retrieved 13 December 2006. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
    Lacey, Louise (1975). Lunaception: a feminine odyssey into fertility and contraception. New York: Coward, McCann & Geoghegan. ISBN 0-698-10674-1.[page needed]
  78. ^ "[1]". Fertility and the Moon Phase Cycle Book reviews, information and research on lunar correlates in fertility cycles[self-published source?]
  79. ^ Singer, Katie. "Fertility Awareness, Food, and Night-Lighting". Wise Traditions in Food, Farming and the Healing Arts, Spring 2004. See section on Night-Lighting.
  80. ^ Harder, Ben (Week of August 28, 2004). "Bright nights kindle cancers in mice". Science News. 166 (9): 141. {{cite journal}}: Check date values in: |date= (help)
  81. ^ Danilenko KV, Samoilova EA (2007). "Stimulatory Effect of Morning Bright Light on Reproductive Hormones and Ovulation: Results of a Controlled Crossover Trial". PLoS clinical trials. 2 (2): e7. doi:10.1371/journal.pctr.0020007. PMC 1851732. PMID 17290302.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  82. ^ Shannon, Marilyn M. (2001). Fertility, cycles & nutrition : how your diet affects your menstrual cycles & fertility (3rd ed.). Cincinnati, OH: Couple to Couple League International. pp. 71–72.
  83. ^ As cited by Adams, Cecil, "What's the link between the moon and menstruation?" (accessed 6 June 2006):
    Abell, George O. (1983). Science and the Paranormal: Probing the Existence of the Supernatural. Scribner Book Company. ISBN 0-684-17820-6. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  84. ^ Cutler WB (1980). "Lunar and menstrual phase locking". Am. J. Obstet. Gynecol. 137 (7): 834–9. PMID 7405975. {{cite journal}}: Unknown parameter |month= ignored (help)
  85. ^ Friedmann E. (1981). "Menstrual and lunar cycles". Am. J. Obstet. Gynecol. 140 (3): 350. PMID 7246643. {{cite journal}}: Unknown parameter |month= ignored (help)
  86. ^ Law SP (1986). "The regulation of menstrual cycle and its relationship to the moon". Acta Obstet Gynecol Scand. 65 (1): 45–8. doi:10.3109/00016348609158228. PMID 3716780.
  87. ^ Zimecki M. (2006). "The lunar cycle: effects on human and animal behavior and physiology". Postepy Hig Med Dosw (Online). 60: 1–7. PMID 16407788.
  88. ^ Kelly, Ivan; Rotton, James; Culver, Roger (1986). "The Moon Was Full and Nothing Happened: A Review of Studies on the Moon and Human Behavior". Skeptical Inquirer. 10 (2): 129–43.. Reprinted in The Hundredth Monkey - and other paradigms of the paranormal, edited by Kendrick Frazier, Prometheus Books. Revised and updated in The Outer Edge: Classic Investigations of the Paranormal, edited by Joe Nickell, Barry Karr, and Tom Genoni, 1996, CSICOP.
  89. ^ Strassmann B. I. (1997). "The biology of menstruation in Homo sapiens: total lifetime menses, fecundity, and nonsynchrony in a natural fertility population". Current Anthropology. 38: 123–9. JSTOR 2744446.

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