I’m a post menopausal woman whose body it completely incapable of producing estrogen. I have zero without HRT. But since I’m having surgery soon, I can’t take them for a couple of weeks. To say that my quality of life has diminished is an understatement. I understand that HRT & BC can increase the risk of clots, especially for smokers (which I have not been for a dozen years now), but why?
In: Biology
It is due to how they are taken and which form they are in.
Estrogens (primarily Estradiol) increase blood clotting even naturally.
However, when taking E orally, it will pass through the liver first before entering the blood, causing most of the medication to be destroyed there. To counteract this, you take a higher dose to ensure enough makes it all the way, or manufacture some that “looks like estrogen” but is more resistant to being metabolized in the liver.
This means that the estrogen concentration in the liver is higher than in the rest of the body, so if you want a pre-menopausal blood level, the liver has a much higher level of estrogen.
The liver is responsible for producing blood clotting factors as well, which means that the much higher estrogen level in your liver (compared to the rest of the body) also causes elevated production of blood clotting.
Synthetic estrogens are also made to specifically last longer in the liver and resist metabolism, such as Ethinylestradiol, common in birth control pills.
A way to counteract this is to use alternative routes that do not go through the liver, ensuring a more equal level of estrogen in the body, greatly reducing this artificially elevated level in your liver leading to increased clotting factor production. A common alternative is transdermal, which is a cream applied to e.g; thighs which will deliver the medication by having it gradually absorb through your skin and into the blood vessels inside your inner thigh.
This is quite common for transgender people who need to stay on estrogen through their whole lives, which greatly increases this build up risk of blood clots
the easy answer: estrogen causes an increase in clot forming factors and a decrease in the regulators of clot formation making it easier to form clots when you don’t want to
specific answer: your body has systems of checks and balances that help regulate normal states. one of the systems is clot formation which helps prevent excessive blood loss. it works through two parts. estrogen affects the second part, the coagulation cascade, increasing levels of factors 2, 7, 8, 10, and fibrinogen all of which are pro-thrombotic, meaning they are pro-clot forming. it also decreases antithrombin and protein S, which help regulate the coagulation cascade and prevent excessive formation. decrease the regulation increases clot formation. it also increases resistance to protein C, another regulator of the coagulation cascade
Latest Answers