Wednesday, December 08, 2004

Why we have bleeding problems... Links/References

At the beginning of the year I posted some links about dysfunctional uterine bleeding (DUB) and one list member (on the fibroid group) asked if I would look into why women tend to have flooding first thing in the morning. Most of you probably know this phenomena whether or not you have DUB -- its when you are sound asleep and suddenly awaken because a big gush of blood is coming out all at once and you run to the bathroom if you can though sometimes you wake up too late and the sheets, your underwear and your nightclothes all need washing.

I wish I had a hematologist to confer with but doctors tend to keep to themselves or just don't overlap with my software oriented social network. I've got a few references here some mechanical and some physiological to causes for bleeding. Since excess estrogen/low progesterone is one theory of part of the cause of fibroids it is interesting to see that the same conditions also set the stage for bleeding problems. Also, I couldn't find references to early morning menstrual bleeding but there was a reference to there being early morning changes in the blood which might be related, at least in action.

"Most very heavy menstrual bleeding does not mean that a woman is shedding substantially more endometrium. The endometrial slough is determined by the size of the uterus and the hormonally induced endometrial thickness. The uterus has large blood vessels that come through the myometrium to feed and supply the endometrium. Really heavy bleeding occurs when the uterine muscle cannot do its job of contracting around these vessels. This is important because after the endometrium is passed out, the basilis layer may be very thin, which could expose the raw muscle surface. This means that the large
vessels can pump blood directly into the uterine cavity if the muscle cannot contract well."

"what frequently happens when excessive amounts of estrogen are secreted. Parts of the endometrium outgrow their blood supply and are discarded but not simultaneously. While the one part recovers another part is discarded and the bleeding continue for prolonged periods. In the illustrations the bleeding might decrease while the one area heals before the the other area starts bleeding."

"Fibroids usually cause excessive cyclic bleeding. The amount of blood loss is increased and /or the duration of the bleeding is increased. The mechanism is probably due to enlargement of the womb, thus increasing the surface area of the endometrium."

"The plasminogen (fibrinolytic) system (Figure 1 ) comprises an inactive proenzyme, plasminogen, that can be converted to the active enzyme, plasmin, that degrades fibrin and that activates matrix metalloproteinases (MMPs), which in turn degrade extracellular matrix(ECM)"
"There is a clear correlation between the circadian variation in the time of onset of myocardial infarction, with the highest incidence at about 8 a.m., and the circadian rhythm of plasma PAI-1 activity, which is also highest early in the morning."

"PGE2 --> vasodilation; PGF2a --> vasoconstriction; progesterone is necessary to increase ararchidonic acid, the precursor to PGF2a. With decreased progesterone there is a decreased PGF2a/PGE2 ratio. Since vasoconstriction is promoted by PGF2a, which is less abundant due to the decrease in progesterone, vasodilation results thereby promoting AUB [Abnormal Uterine Bleeding]" (no longer available)

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