Bleeding Patterns & Amount of Flow
I thought it might be interesting to have a section devoted to how women bleed.
OK, some might find this gross, but it's interesting, as not all women bleed the same.

.:{Amount of Flow}:..:{Bleeding Patterns}:..:{Cloth Pad Main Menu}:.

Amount of Flow
The "average" amount of blood lost during a period can be very different between women.  What is "normal" for one woman will seem too little or too much for another.  Another problem when measuring the flow is that not all of what makes up menstrual flow is actual "blood", only about half of it is, and some "average" amounts are calculated using the blood content, not total volume of what you loose as menstrual flow.

According to the Monash University's health website:

"normal menstrual blood loss has a mean volume of 30-40 mL (Fig.1). The range of normal menstrual blood loss is typically 10-80 mL."
http://www.med.monash.edu.au/ob-gyn/research/menorr.html

1). Weighing used and fresh pads, taking the weight difference to be the blood lost.
2). Using images of disposable pads rated from "spotting" to "soaked" to calculate flow, with the pictures corresponding to pre determined fluid amounts (eg an image of a soaked pad might be considered to be equal to 10mls)
3). Chemical tests (alkaline hematin) are done to measure the actual blood content found on the pads.

A pictorial assessment - such as comparing your flow to that of images of blood on a pad cannot be an accurate way to measure volume of blood lost, as the pads absorbency is designed to pull wetness from the top and may disguise the actual amount of blood lost.... I know that I've looked at the top of a pocket style pad and then been surprised at the amount of blood on the inserts inside it, as they held more blood than I'd imagined.  If a sample pad is used and certain volumes of liquid poured onto it as the method of determining how much volume the pads equate to (which is how I assume they calculate those pictorial tests).... different brands of disposable pad would presumably give different levels of absorption and have a different appearance, so it would only be accurate if the same type of pad is used by the woman as was used for the sample.

Weighing pads would be rather time consuming, but would give a more accurate measurement than comparing your flow to images.  However sweat and vaginal secretions may also be on the pad, which may affect its weight.  Also some evaporation may occur too, and dry blood would presumably weigh less than wet blood.

If you've ever wondered why some women like what you consider to be a nappy as a pad.... or how some women can wear a mere scrap of fabric without leaking, it may surprise you to know that not all women bleed the same way.