In the first month of pregnancy, the Jueyin meridian of the foot nourishes the fetus; in the second month, the Shaoyang meridian of the foot; in the third month, the pericardium meridian of the hand; in the fourth month, the Shaoyang meridian of the hand; in the fifth month, the Taiyin meridian of the foot; in the sixth month, the Yangming meridian of the foot; in the seventh month, the Taiyin meridian of the hand; in the eighth month, the Yangming meridian of the hand; in the ninth month, the Shaoyin meridian of the foot; and in the tenth month, the Taiyang meridian of the foot. Each yin and yang meridian nourishes the fetus for thirty days. If the Taiyang meridian of the hand and the Shaoyin meridian do not nourish, it leads to menstruation below and produces milk above to nourish the fetus.