Lean hard-training women athletes may menstruate less frequently or not at all.
身材瘦削而且训练艰苦的女运动员行经可能不那么频繁，或者根本不来月经。
Why is the woman always met menstruate?
女人为什么总会有月经?
期刊摘选
She began to menstruate regularly at 13 at intervals of 28~32 days with slight dysmenorrheal.
她于13岁开始有正常的月经,周期为28~2天,有轻度的月经痛.
期刊摘选
Whether does menstruate of the rice before menstruation adumbrate to come smoothly also classics?
月经前米有月经预兆是否也顺利来经?
期刊摘选
She began to menstruate regularly at 13 at intervals of 28～32 days with slight dysmenorrheal.
她于13岁开始有正常的月经,周期为28～32天,有轻度的月经痛.
《简明英汉词典》
Some girls may first ovulate even before they menstruate.
一些女孩的第一次排卵甚至可能出现在初潮之前。
柯林斯例句
"She started menstruating at the age of 11"