《素问》曰∶女子七岁，肾气盛，齿更发长，二七而天癸至，任脉通，太冲脉盛，月事以时而下，故能
有子。
《灵枢》曰∶冲脉起于胞中，出于气街，前行于胸，伏行于背，上出颃颡，渗灌诸阳，下入于足，注诸络，
为十二经脉之海，其出入皆少阴经以行，故为血海。
《素问》曰∶天地温和，则经水安静。天寒地冻，则经水凝泣。天暑地热，则经水沸溢。卒风暴起，则经
水波涌而陇起。邪之入于脉也，寒则血凝泣，天暑则气淖泽，虚邪因而入客，亦如经水之得风也。
慎斋按∶以上经论三条，序女子月事，始本太冲脉盛，而冲脉则起胞中，即为血海，此经水之源也。但经水
得寒则凝，得热则行，尝与天地寒暑之气相应，而调经者可以知所务矣。
王太仆曰∶冲为血海，诸经朝会，男子则运而行之，女子则停而止之，谓之血室。经云，任脉通，冲脉盛，男
既营运，女既停止。
营运者，无积而不满，动也。停止者，有积而能满，静也。不满者，阳也，气也。能满者，阴也，血也。故满
者以时而溢，谓之信。男子以气运，故阳气应日而一举。女子以血满，故阴血应月而一下。
马玄台曰∶任冲二脉，奇经八脉之二也。经云任主胞胎，冲为血海。今二脉俱通，月事而下。《灵枢》云∶
冲脉、任脉，皆起于胞中。又云∶冲脉为血之海。又云∶血海有余。按∶血海之海，虽曰既行而空，至七日后
而渐满，如月之盈亏相似。当知血海之有余，以十二经皆然，非特血海之满也，故始得以行耳。
《素问》说：女子到了七岁，肾气充盛，牙齿更换，头发生长；到了十四岁（二七），天癸（促进生殖机能成熟的物质）到来，任脉通畅，太冲脉旺盛，月经按时来潮，因此能够受孕。
《灵枢》说：冲脉起始于胞宫（子宫），出于气街（腹股沟动脉搏动处），前行于胸部，伏行于背部，向上出于颃颡（鼻咽部），渗灌各阳经，向下进入足部，注入各络脉，是十二经脉气血汇聚的海，其出入都伴随少阴经运行，所以被称为血海。
《素问》说：天地气候温和，则经水（月经）平静；天气寒冷大地冻结，则经水凝滞不畅；天气暑热大地炎热，则经水沸腾溢出；突然刮起暴风，则经水波涛汹涌并隆起。邪气侵入脉中，寒邪则使血液凝滞，天暑则使气机淖泽（湿润流动），虚邪趁机侵入客居体内，也如同经水遇到风一样。
慎斋按语：以上三条经典论述，叙述了女子月经的起源，起始于太冲脉的旺盛，而冲脉起始于胞中，就是血海，这是经水的源头。但是经水遇到寒邪则凝滞，遇到热邪则运行，曾经与天地寒暑之气相应，调理月经的人可以知道所应关注的要点了。
王冰（王太仆）说：冲脉为血海，各经气血朝会于此，男子则推动运行它，女子则停留止蓄它，称之为血室。经书说，任脉通畅，冲脉旺盛，男子既然营运，女子既然停止。所谓营运，是没有积滞而不满足，属于动的性质；所谓停止，是有积滞而能充满，属于静的性质。不满足的是阳，是气；能充满的是阴，是血。所以充满的时候按时溢出，称为信期（定期）。男子以气运化，所以阳气应合太阳日行一度而举发；女子以血满盈，所以阴血应合月亮盈亏而下注。
马莳（马玄台）说：任脉和冲脉，是奇经八脉中的两条。经书说任脉主司胞胎，冲脉为血海。现在这两条经脉都通畅，月经便下行。《灵枢》说：冲脉、任脉，都起始于胞中。又说：冲脉是血的海洋。又说：血海有余。按语：血海的“海”，虽然说是经行之后变空，但到七日后又逐渐充盈，就像月亮的盈亏相似。应当知道血海的有余，是因为十二经气血皆然，不仅仅是血海的满盈，所以开始得以行经。
The *Suwen* (Basic Questions) states: When a girl reaches seven years of age, her Kidney Qi becomes abundant, her teeth are replaced, and her hair grows. At fourteen years old (two sevens), Tian Gui (the substance promoting reproductive maturation) arrives, the Ren Mai (Conception Vessel) becomes unobstructed, and the Taichong Mai (Thoroughfare Vessel) becomes prosperous. Her menstruation occurs at regular intervals, thus enabling her to conceive.
The *Lingshu* (Spiritual Pivot) states: The Chong Mai (Penetrating Vessel) originates in the Baozhong (uterus), emerges at the Qiqiao (inguinal region where the femoral artery pulses), moves forward through the chest, runs deep along the back, emerges upward at the Hangsang (nasopharynx), permeates and irrigates the Yang meridians, descends into the feet, and pours into the collateral vessels. It serves as the Sea of Blood for the Twelve Primary Meridians. Its pathways run alongside the Shaoyin Meridian, hence it is called the Sea of Blood.
The *Suwen* states: When heaven and earth are mild and warm, the menstrual water remains calm. When heaven is cold and earth frozen, the menstrual water coagulates and flows sluggishly. When heaven is hot and earth scorching, the menstrual water boils and overflows. When sudden storms arise, the menstrual water surges like waves and rises. When pathogenic factors enter the vessels, cold causes blood to coagulate and flow sluggishly; summer heat makes Qi moist and fluid. Deficient pathogens take this opportunity to invade and reside within, similar to how menstrual water reacts to wind.
Shen Zhai’s commentary: The above three classic discussions outline the origin of female menstruation, which begins with the prosperity of the Taichong Mai. Since the Chong Mai originates in the Baozhong, it constitutes the Sea of Blood, which is the source of menstrual water. However, menstrual water coagulates when exposed to cold and flows when exposed to heat, corresponding to the seasonal changes of heaven and earth. Those who regulate menstruation can thereby understand their primary objectives.
Wang Bing (Wang Taipu) states: The Chong Mai is the Sea of Blood, where all meridians converge. In men, it is transported and circulated; in women, it is retained and stopped, referred to as the Blood Chamber (Xueshi). The classics state that when the Ren Mai is unobstructed and the Chong Mai is prosperous, men circulate while women retain. Circulation implies no accumulation and a state of insufficiency, characterized by movement. Retention implies accumulation and fullness, characterized by stillness. Insufficiency corresponds to Yang and Qi; fullness corresponds to Yin and Blood. Therefore, when full, it overflows at its proper time, termed "trustworthy" (regular cycle). Men rely on Qi for transport, so Yang Qi responds to the sun's daily cycle with erection. Women rely on Blood for fullness, so Yin Blood responds to the moon's monthly cycle with descent.
Ma Shi (Ma Xuantai) states: The Ren Mai and Chong Mai are two of the Eight Extraordinary Vessels. The classics state that the Ren Mai governs conception and pregnancy, while the Chong Mai is the Sea of Blood. Now that both meridians are unobstructed, menstruation descends. The *Lingshu* states that the Chong Mai and Ren Mai both originate in the Baozhong. It further states that the Chong Mai is the Sea of Blood and that there is an excess in the Sea of Blood. Commentary: Although the Sea of Blood empties after menstruation, it gradually fills again after seven days, resembling the waxing and waning of the moon. One should understand that the "excess" in the Sea of Blood applies generally to the Twelve Meridians, not just the fullness of the Sea of Blood itself, which allows menstruation to commence.