By two years of age, none are left, essentially causing " menopause before menarche" .

在患儿两岁时，已基本没有卵细胞保留，导致“初潮前的更年期”。

There are many causes of secondary amenorrhea, and when they occur before menarche, all of these can also cause primary amenorrhea.

有许多原因会导致继发性闭经，而当它们在初潮前发生时，都会导致原发性闭经。

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

原发性闭经指女性在16周岁前没有初次月经（即初潮），尽管生长发育、进入青春期均无异常。

What about two-thirds of rural high school girls in India who don't even understand what their bodies are going through at menarche?

印度三分之二的农村高中女生甚至不了解她们的身体在月经初潮时经历了什么？

This happens because the missing X chromosome leads to accelerated ovarian follicle depletion, so that by two years old, none are left, essentially causing " menopause before menarche" .

这是因为X染色体的丢失导致卵巢滤泡消耗加速，从而造成卵巢功能在2岁前便所剩无几，最终导致“初潮前绝经”。

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岁时没有初潮，且没有出现青春期发育征兆，也要考虑是否为原发性闭经；青春期发育指第二性征发育，如乳房发育。

That's why there's an increased risk of breast cancer with things that increase the number of menstrual cycles - like early age of menarche, which is the first menstrual bleeding, and late age of menopause.

这就解释了为什么月经次数较多的人患乳腺癌的几率更高，如初潮过早或停经过晚者。

Because it causes streak ovaries, Turner syndrome is also the most common cause of primary amenorrhea, which is when a female has not begun breast development by age 13 or hasn't had menarche by age 15.

由于会导致条索状卵巢，因此特纳综合征也是原发性闭经的最常见原因；原发性闭经是指女性在13岁之前没有乳房发育，或到15岁尚未月经初潮。