the blood we shed
There is a common belief, among Asians in general and Filipinas in particular, that the more we bleed during our menses, the more we are cleansed. While this is partially true, the amount of blood you find on your pads or tampons does not determine the level at which you are purified.
The female body requires the participation of the brain, the ovaries, and the uterus to regulate the menstrual cycle. Estrogen and Progesterone are the two most important hormones that determine how profuse or how long your menses flow.
During the first day of your period, the levels of Estrogen and Progesterone are at their lowest. These low levels of Estrogen and Progesterone in the blood signal the brain to produce hormones that encourage the follicles in the ovaries to grow. As the follicles in the ovary are stimulated to grow, they produce Estrogen which in turn has a positive feedback mechanism on the ovaries further encouraging the follicles to grow.
Estrogen is an important female hormone. During puberty, it is responsible for making our bodies take shape (think widening hips and blossoming breasts), and every month, it makes the lining of the uterus called the endometrium thicken. This process prepares the uterus for the successful implantation of the fertilised egg. The uterus is the organ of the body responsible for housing and nurturing the baby. It has 3 layers — the outermost covering called the serosa, a thick muscular layer called the myometrium, and the innermost and most dynamic layer called the endometrium.
As the follicles continue to grow with the help of the Follicle Stimulating Hormone (FSH) and the positive feedback mechanism of Estrogen, a dominant follicle is produced. When it grows big enough, it explodes and extrudes an ovum (or an egg) towards the fallopian tube. This process is called ovulation, and when the sperm meets the egg, fertilisation happens. This fertilised egg then travels towards the uterus where it implants in the thickened uterine endometrium resulting in a pregnancy.
The follicle that produces the egg becomes a corpus luteum. On Ultrasound, it is the structure that indicates that ovulation has occurred. It is important because it produces Progesterone, the hormone that stabilises the growth of the endometrium ensuring that the follicle implants in the best possible conditions. The corpus luteum supplies the progesterone needed for maintaining the pregnancy while the placenta is still developing. If the pregnancy progresses, both Estrogen and Progesterone increase in amount. But if fertilisation did not happen, both Estrogen and Progesterone decrease in amount and the uterine endometrium is shed, resulting in bleeding that we have come to know as menstruation.
So basically, what comes out of the vagina during menses is not entirely blood, it is mostly the uterine lining that thickened during the cycle which is why you get bits and pieces or even blood-colored clots.
