Which would explain why amenorrhea is most common among ballet dancers, gymnasts, and long distance runners.

这能解释为什麽经对芭蕾舞者 体操选手及长跑运动员来说很常见。

In females, primary sex characteristic dysfunction includes amenorrhea or absence of menstruation, or oligomenorrhea or irregular menstrual cycle.

在女中，第一征的功能障碍包括经，即无月经，或月经减少，即月经周期不规则。

When this happens, TRH also stimulates prolactin release - so hyperprolactinemia and amenorrhea occur.

与此，TRH刺激泌乳素的分泌，所以会出现高泌乳素血症和经。

Ok, now, coming back to amenorrhea.

好，现在说回到经。

Interestingly, hypothyroidism - a condition where there's low levels of thyroid hormones - can also cause amenorrhea.

有趣的是，甲腺功能减退症，一种由于甲腺激素合成及分泌减少导致的疾病，可能会导致经。

A rarer cause of primary amenorrhea is androgen insensitivity syndrome.

导致原经的一个罕见原因是雄激素不敏感综合征。

Finally, endocrine disorders can also cause primary amenorrhea.

最后，内分泌疾病会导致原经。

With functional hypothalamic amenorrhea due to anorexia, there's significant weight loss and decreased bone density which can cause fractures.

由于厌食导致的功能下丘脑经患者往往减重过度且骨密度下降，易致骨折。

The most common cause of primary amenorrhea is Turner syndrome, where one X chromosome is either completely or partially absent.

最可能的原经原因是Turner综合征：有一个X染色体完全或者部分缺失。

The most common cause of secondary amenorrhea is pregnancy.

最可能的继经原因是怀孕。

Issues with the pituitary gland can also cause secondary amenorrhea.

垂体的问题会导致继经。

Another condition that affects the hypothalamic-pituitary-ovarian axis and can be responsible for secondary amenorrhea is polycystic ovary syndrome.

另一种能影响下丘脑-垂体-卵巢轴并可能导致继经的疾病是多囊卵巢综合症。

Primary amenorrhea is when a female hasn't had her first menstruation, called menarche, by age 16, despite normal growth and having started puberty.

原经指女在16周岁前没有初次月经（即初潮），尽管生长育、进入青春期均无异常。

The one symptom of both primary and secondary amenorrhea is, well, the absence of menstruation.

原和继经共有的一个症是没有月经。

Next, there's functional hypothalamic amenorrhea, which is when there is a decrease in GnRH secretion, leading to low levels of LH, FSH, and estrogen.

其次是功能下丘脑经，即由于GnRH分泌下降导致LH、FSH和雌激素水平下降。

In practice, nomadic hunter-gatherers space their children about four years apart by means of lactational amenorrhea, sexual abstinence, infanticide, and abortion.

实际上，游牧狩猎采集者通过哺乳经、禁欲、杀婴和堕胎等手段将孩子间隔大约四年。

All right, as a quick recap… amenorrhea is the abnormal absence of menstruation in females of reproductive age.

好！快速回顾一下：经指育龄期女无月经或月经异常停止。

An early symptom is agalactorrhea, whereas late symptoms include amenorrhea, low blood pressure, low blood sodium, low blood glucose levels, as well as fatigue and muscle loss.

早期症包括产后无乳，而晚期症包括经、低血压、低血钠、低血糖、疲劳和肌肉萎缩。

Primary amenorrhea is also suspected when a female hasn't had menarche by age 13 and doesn't show signs of puberty, which include developing secondary sexual characteristics like breasts.

当女孩13岁没有初潮，且没有出现青春期育征兆，要考虑是否为原经；青春期育指第二征育，如乳房育。

Later symptoms include amenorrhea, an absence of a normal menstrual cycle, even after a period of lactation, which is due to a lack of luteinizing hormone and follicle stimulating hormone.

晚期的症包括经，即月经周期不正常，甚至就在哺乳期后出现，这是由于缺乏黄体生成素和卵泡刺激素。