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Abstract
Normal bleeding occurs throughout a woman's life cycle, from puberty to menopause. This bleeding is caused by the interaction of specific hormones. The optimal functioning of these hormones is fundamental to a woman's health. Nurses need to be aware of the physiology related to bleeding throughout a woman's life cycle.
... During childhood, the hypothalamus is sensitive to low levels of estrogen, which exert a negative feedback effect inhibiting hypothalamic activity. The exact trigger for puberty and menarche is still not well understood; the appearance of related events, as well as the timing of menarche, varies greatly and is influenced by nutrition, heredity, state of health, percentage of body fat, growth hormone and other growth factors, and maturation of the hypothalamic-pituitary axis, which is itself dependent on multiple factors [2][3][4] . In general, puberty is initiated in females when the hypothalamus matures and becomes less sensitive to negative feedback, promoting an increase in the secretion of GnRH by the neurosecretory cells within the hypothalamus, which in turn triggers the anterior pituitary to begin the secretion of the gonadotropic hormones, LH and FSH. ...
... Sufficient quantities of FSH and LH stimulate ovarian follicular development, the development of secondary sex characteristics, and an increased release of female sex steroids (estrogen and progesterone) from the ovaries [2] . Estrogen and progesterone continue to increase throughout puberty, and play a key role in both physical and sexual maturation [3] . Throughout the phases of the menstrual cycle, FSH promotes the development of the follicle and the secretion of estrogen by the ovaries, while LH stimulates ovulation and the secretion of estrogen and progesterone. ...
... A normal cycle is often described as being on the average 28 days in length, but in reality, a 28-day cycle occurs in only 12.4% of all cycles. Studies on the length of regular menses have shown variations in the length of 'normal' as ranging from 21 to 35 days [2,3] . Menstrual duration also varies considerably, with normal flow lasting for an average of 2-8 days [2,3] . ...
Die in den letzten Jahrzehnten beobachtete Entwicklung, dass Kinder bereits in jungen Jahren verstärkt Leistungssport betreiben, hat Bedenken hinsichtlich der möglichen Auswirkungen des Leistungssports auf das Wachstum und die körperliche Reifung dieser Kinder hervorgerufen. Kennzeichnend für die Pubertät beim Menschen sind starke hormonelle Veränderungen, die sowohl zur körperlichen als auch zur sexuellen Reifung führen. Da Leistungssport vor der Pubertät in Kombination mit den möglichen metabolischen Folgen einer Ernährungsrestriktion die Funktion des Hypothalamus-Hypophysen-Systems verändern kann, hat man die Vermutung geäussert, dass es für die Verzögerung der Menarche und der sexuellen Reifung bei Sportlerinnen u.a. entscheidend ist, in welchem Alter diese mit dem Leistungssport beginnen. Andererseits behaupten einige Studien, eine verzögerte Menarche sei eher auf genetische Faktoren zurückzuführen. Mädchen, bei denen die körperliche Reifung später einsetzt, wählen häufig eine Sportart, bei der sich ein kleiner oder sehr schlanker Körperbau als vorteilhaft erweist, oder werden von Trainern für eine solche Sportart angeworben. Die Körperzusammensetzung wurde auch als Erklärung für die bei Spitzensportlerinnen beobachtete Verzögerung der Menarche und Menstruationsstörungen herangezogen. Bei jugendlichen Sportlerinnen, die Sportarten betreiben, bei denen das Körpergewicht eine Rolle spielt, wurde über eine höhere Prävalenz von Menstruationsstörungen berichtet als bei Sportlerinnen, die in anderen Sportarten aktiv sind. Es gibt jedoch, wie vor kurzem behauptet, keinen direkten kausalen Zusammenhang zwischen Beleibtheit und Fortpflanzung, und tatsächlich werden die Fortpflanzungsfunktionen bei Frauen von der Energieverfügbarkeit und nicht vom Körperfett geregelt. Zur weiteren Untersuchung dieser Wechselwirkung zwischen kurzfristigen Schwankungen der verfügbaren Energie und der durch den Sport bedingten sekundären Amenorrhö bei jugendlichen Sportlerinnen bedarf es weiterer Forschungsbemühungen. Schlussfolgerung ist, dass angesichts der vielen Faktoren, die sich nachweislich auf die Menarche und die Menstruation auswirken, bisher noch unklar ist, welche Rolle das Sporttraining alleine als ursächlicher Faktor für eine verzögerte Pubertät und Menstruationsstörungen bei jungen Sportlerinnen spielt. Forschungsarbeiten in Form von Längsschnittstudien müssen durchgeführt werden, um festzustellen, ob die zwischen Sportlerinnen und Nichtsportlerinnen beobachteten Unterschiede in der körperlichen Reifung genetisch oder umweltbedingt sind und welches Gleichgewicht zwischen diesen beiden Faktoren herrscht.
... During childhood, the hypothalamus is sensitive to low levels of estrogen, which exert a negative feedback effect inhibiting hypothalamic activity. The exact trigger for puberty and menarche is still not well understood; the appearance of related events, as well as the timing of menarche, varies greatly and is influenced by nutrition, heredity, state of health, percentage of body fat, growth hormone and other growth factors, and maturation of the hypothalamic-pituitary axis, which is itself dependent on multiple factors [2][3][4] . In general, puberty is initiated in females when the hypothalamus matures and becomes less sensitive to negative feedback, promoting an increase in the secretion of GnRH by the neurosecretory cells within the hypothalamus, which in turn triggers the anterior pituitary to begin the secretion of the gonadotropic hormones, LH and FSH. ...
... Sufficient quantities of FSH and LH stimulate ovarian follicular development, the development of secondary sex characteristics, and an increased release of female sex steroids (estrogen and progesterone) from the ovaries [2] . Estrogen and progesterone continue to increase throughout puberty, and play a key role in both physical and sexual maturation [3] . Throughout the phases of the menstrual cycle, FSH promotes the development of the follicle and the secretion of estrogen by the ovaries, while LH stimulates ovulation and the secretion of estrogen and progesterone. ...
... A normal cycle is often described as being on the average 28 days in length, but in reality, a 28-day cycle occurs in only 12.4% of all cycles. Studies on the length of regular menses have shown variations in the length of 'normal' as ranging from 21 to 35 days [2,3] . Menstrual duration also varies considerably, with normal flow lasting for an average of 2-8 days [2,3] . ...
... During childhood, the hypothalamus is sensitive to low levels of estrogen, which exert a negative feedback effect inhibiting hypothalamic activity. The exact trigger for puberty and menarche is still not well understood; the appearance of related events, as well as the timing of menarche, varies greatly and is influenced by nutrition, heredity, state of health, percentage of body fat, growth hormone and other growth factors, and maturation of the hypothalamic-pituitary axis, which is itself dependent on multiple factors [2][3][4] . In general, puberty is initiated in females when the hypothalamus matures and becomes less sensitive to negative feedback, promoting an increase in the secretion of GnRH by the neurosecretory cells within the hypothalamus, which in turn triggers the anterior pituitary to begin the secretion of the gonadotropic hormones, LH and FSH. ...
... Sufficient quantities of FSH and LH stimulate ovarian follicular development, the development of secondary sex characteristics, and an increased release of female sex steroids (estrogen and progesterone) from the ovaries [2] . Estrogen and progesterone continue to increase throughout puberty, and play a key role in both physical and sexual maturation [3] . Throughout the phases of the menstrual cycle, FSH promotes the development of the follicle and the secretion of estrogen by the ovaries, while LH stimulates ovulation and the secretion of estrogen and progesterone. ...
... A normal cycle is often described as being on the average 28 days in length, but in reality, a 28-day cycle occurs in only 12.4% of all cycles. Studies on the length of regular menses have shown variations in the length of 'normal' as ranging from 21 to 35 days [2,3] . Menstrual duration also varies considerably, with normal flow lasting for an average of 2-8 days [2,3] . ...
The increasing involvement of young children in intense physical training over the past several decades has generated concerns as to its potential effects on children's growth and maturation. Puberty in humans is characterized by large hormonal changes resulting in both physical and sexual maturation. Since intense training prior to puberty, together with the potential metabolic effects of dieting, can alter hypothalamic-pituitary function, the time at which athletic training is initiated has been implicated as a factor in delayed menarche and sexual maturation in female athletes. On the other hand, some studies have suggested that delayed menarche is likely due to genetic factors. Girls who mature later often self-select or are recruited by coaches into sports that favor small or very lean bodies. Body composition has also been used to explain both delayed menarche and menstrual irregularities observed among elite athletes. A higher prevalence of menstrual dysfunction has been reported for adolescent athletes participating in weight-dependent sports as compared to that observed in other sports. However, as recently suggested, there is no direct cause-effect association between fatness and reproduction and, in actual fact, energy availability, and not body fat, regulates reproductive function in females. More research is warranted to further investigate this interaction between short-term changes in fuel availability and athletic amenorrhea in female adolescents. It is concluded that, given the many factors that have been shown to influence menarche and menstruation, the role played by physical training alone as a causative factor in the later onset of puberty and menstrual irregularities in active young females is still unclear. Research involving longitudinally designed studies is required to identify whether the maturity differences observed between female athletes and non-athletes are the result of nature or nurture, and what the balance between the two factors is.
... Thus, why pubertal timing is not affected, when other sexdimorphic (and potentially prenatally influenced) characteristics are, is unclear. Perhaps it is related to the fact that in young women a sufficient amount of adipose tissue for converting testosterone to estrogen and, thus, achieving the estrogen positive feedback is necessary for the activation of hypothalamic-pituitary-ovarian function and the onset of the menstrual cycle (Hamm, 1991). Thus, if lesbians weigh more than heterosexual women as result of constitutional or dietary factors, which has been demonstrated in a number of studies (see Bogaert, 1998), then this may counteract any later timing in puberty that might occur as a result of a partial androgenization of the hypothalamus in lesbians. ...
The relations between sexual orientation and age of puberty in both men and women were examined in a national probability sample of the United States. The sample was the National Health and Social Life Survey (E. O. Laumann, J. H. Gagnon, R. T. Michael, & S. Michaels, 1994), which contains 3432 cases. Gay/bisexual men reported an earlier age of puberty (e.g., age of first pubic hair) relative to heterosexual men, but lesbian/bisexual women did not report a different age of puberty (i.e., age of menarche) than heterosexual women. These results confirm findings from prior research examining age of puberty using nonrepresentative samples and add to a body of literature suggesting that gay/bisexual men may score, on average, in the female-typical direction on certain sex-dimorphic physical and developmental characteristics.
... Thus, why pubertal timing is not affected, when other sexdimorphic (and potentially prenatally influenced) characteristics are, is unclear. Perhaps it is related to the fact that in young women a sufficient amount of adipose tissue for converting testosterone to estrogen and, thus, achieving the estrogen positive feedback is necessary for the activation of hypothalamic-pituitary-ovarian function and the onset of the menstrual cycle (Hamm, 1991). Thus, if lesbians weigh more than heterosexual women as result of constitutional or dietary factors, which has been demonstrated in a number of studies (see Bogaert, 1998), then this may counteract any later timing in puberty that might occur as a result of a partial androgenization of the hypothalamus in lesbians. ...
Research using non-representative samples indicates that certain sex-dimorphic physical, developmental and behavioral variables predict sexual orientation. In this study, three sex-dimorphic physical development variables-height, weight, and age of puberty/sexual maturation-and sexual orientation were examined in a British national probability sample (N=18,876). Women with same-sex inclinations (particularly bisexuals) had an earlier first sexual experience (approx. 1.4 years) and were taller (approx. 1 cm) than heterosexual women, but the height/sexual orientation relationship was complex. Lesbian/bisexual women did not differ from heterosexual women in age at menarche or in weight. Men with same-sex inclinations (particularly bisexuals) had an earlier first sexual experience relative to heterosexual men (approx. 3 months). Homosexual men did not significantly differ from heterosexual men in height or in weight, although there was some evidence that bisexual men were taller than heterosexual men (approx. 1 cm). The results challenge some prior research on sexual orientation and physical development using non-representative samples.
La creciente participación de niños pequeños en el entrenamiento físico intensivo, durante las últimas décadas, ha generado temores con respecto a sus efectos potenciales sobre el crecimiento y la maduración de los niños. La pubertad en el humano se caracteriza por cambios hormonales considerables, que resultan tanto en maduración física como en maduración sexual. Dado que un entrenamiento intensivo antes de la pubertad, junto a los efectos metabólicos potenciales del seguimiento de una dieta, puede alterar la función hipotalámica e hipofisaria, el momento en que se inicia el entrenamiento atlético ha sido implicado como un factor en el retraso de la menarquia y la maduración sexual en atletas femeninas. Por otra parte, en algunos estudios se ha dejado entrever la probabilidad de que el retraso de la menarquia puede deberse a factores genéticos. Las niñas que maduran más tardíamente, a menudo se autoseleccionan o son reclutadas por preparadores para deportes que favorecen cuerpos de tamaños reducidos o muy delgados. También se ha utilizado la composición corporal para explicar el retraso de la menarquia y las irregularidades menstruales que se observan en atletas de elite. Se ha descrito una mayor prevalencia de disfunción menstrual en atletas adolescentes que participan en deportes dependientes del peso, en comparación con lo que se observa en otros deportes. No obstante, tal como se ha dejado entrever recientemente, no existe una relación directa entre causa y efecto entre la obesidad y la reproducción y, en realidad, la función reproductora en las mujeres está regulada por la disponibilidad energética y no por la grasa corporal. Está justificado intensificar la investigación para indagar adicionalmente esta interacción entre los cambios a corto plazo en la disponibilidad de los combustibles y la amenorrea atlética en adolescentes femeninas. Se llega a la conclusión de que, teniendo en cuenta los numerosos factores que, según se ha comprobado, influyen sobre la menarquia y la menstruación, el papel desempeñado por el mero entrenamiento físico como factor causal del inicio más tardío de la pubertad y de las irregularidades menstruales en niñas físicamente activas sigue siendo dudoso. Es imprescindible una investigación basada en estudios diseñados longitudinalmente para identificar si las diferencias en la maduración, observadas entre atletas femeninas y niñas que no practican actividades atléticas, son el resultado de la naturaleza o la nutrición, y cuál es el equilibrio entre ambos factores.
Ces dernières décennies, la participation croissante de jeunes enfants à un entraînement physique intensif a été à l’origine de préoccupations quant aux effets potentiels de cette situation sur la croissance et la maturation. La puberté se caractérise chez l’être humain par d’importantes modifications hormonales responsables de la maturation physique et sexuelle. Un entraînement intensif avant la puberté, ainsi que les effets métaboliques potentiels du régime alimentaire adopté, peuvent altérer la fonction hypothalamo-hypophysaire, et le moment auquel l’entraînement athlétique débute a été impliqué à titre de facteur de retard de la ménarche et de la maturation sexuelle chez les sportives. D’autre part, certaines études ont suggéré qu’un retard de la ménarche est probablement dû à des facteurs génétiques. Les jeunes filles qui sont matures plus tardivement sélectionnent souvent elles-mêmes des sports qui favorisent une petite taille ou une grande minceur, ou sont recrutées par les entraîneurs pour ceux-ci. La composition corporelle a été également utilisée afin d’expliquer simultanément le retard de la ménarche et les irrégularités menstruelles observées chez les sportives de haut niveau. Une prévalence plus élevée des dysfonctions menstruelles a été décrite chez des adolescentes pratiquant des sports dépendant du poids, comparativement à celle observée avec d’autres activités sportives. Toutefois, comme récemment suggéré, il n’existe aucune relation directe de cause à effet entre la corpulence et la reproduction et, de fait, c’est la disponibilité de l’énergie, et non les tissus adipeux, qui régule la fonction reproductive chez la femme. Des recherches supplémentaires sont justifiées afin de mieux explorer cette interaction entre les modifications à court terme de la disponibilité de l’énergie et l’aménorrhée due au sport chez l’adolescente. Nous concluons que, en raison des nombreux facteurs influençant de façon avérée la ménarche et la menstruation, le rôle du seul entraînement physique à titre de facteur causal d’un retard pubertaire et d’irrégularités menstruelles chez les jeunes femmes sportives est encore mal défini. Des recherches comportant des études longitudinales sont nécessaires afin de déterminer si les différences de maturité observées entre des jeunes femmes sportives ou non résultent de la nature ou de la nutrition, et quel est l’équilibre entre ces deux facteurs.
To assess the prevalence of delayed menarche and abnormal menstrual patterns, as well as the association of menstrual status with physical training in elite rhythmic gymnasts from Greece and Canada.
Fifteen Greek (mean (SEM) age 14.5 (0.2) years) and 30 Canadian (mean (SEM) age 14.7 (0.4) years) rhythmic gymnasts were surveyed for age at menarche, menstrual frequency, and training profile, and measured for height, weight, and percentage body fat (%BF). Seventy eight healthy adolescents served as country specific non-active controls: 38 Greek non-athletes (mean (SEM) age 14.5 (0.1) years) and 40 Canadian non-athletes (mean (SEM) 14.2 (0.1) years).
Of the Greek gymnasts, 79% had not yet menstruated compared with 34% of the Canadian gymnasts. Menarche was significantly (p<0.01) delayed in the rhythmic gymnasts (composite mean 13.8 (0.3) years, n = 45) compared with the controls (composite mean 12.5 (0.1) years, n = 78). There was no significant difference between Greek and Canadian gymnasts for the age at menarche (14.2 (0.3) v 13.6 (1.2) years respectively). Menstrual irregularities were reported in 78% (61% oligomenorrhoeic and 17% amenorrhoeic) of the menarcheal athletes. Menarcheal gymnasts were found to be significantly (p<0.05) taller and heavier, with a higher %BF and a lower training frequency and training duration (p<0.05) than the premenarcheal gymnasts. Overall, the mean %BF of the gymnasts was significantly lower (p<0.05) than that of the control subjects. The Canadian controls exhibited a significantly (p<0.05) greater %BF than the Greek controls of the same age.
Delayed menarche, menstrual irregularities, and low body fat are common in elite rhythmic gymnasts. Premenarcheal gymnasts train more often and for longer, and have a lower body mass index and less body fat, than menarcheal gymnasts. Prospective studies are needed to explore further these and other factors associated with delayed menarche and menstrual irregularities in female athletes.
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