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one of the most amazing moments for a woman is when she finds out she's pregnant or I guess I should say when her brain finds out because her body is already aware of it from several weeks before so much so that by the time a woman finds out that she's about to be a mom her body has already undergone several changes to prepare for that growing baby or in the first and most important changes that the body makes is that it realizes that it needs more oxygen which means that it needs more red blood cells to carry the oxygen within the blood and in order to do that the level of a hormone called erythropoietin called a referral erythropoietin have to increase right and erythropoietin is this hormone that stimulates the bone marrow to increase production of red blood cells and those levels don't increase by just a little they increase up to 50% in fact if the pregnant body could have its way with things the amount of red blood cells would increase by something like twenty to thirty percent over the course of a pregnancy but what actually ends up happening a lot of the time in pregnancy is that women become anemic so the hemoglobin and the hematocrit values which are which are measures of the amount of red blood cells you have in the blood decrease instead of increasing they decrease and that can happen for a couple of different reasons the first reason is something that happens in normal pregnant women and that is that the plasma volume which plasma is is like the liquid component of blood the plasma volume increases more than the red blood cell mass so even though the amount of red blood cells is increasing the concentration of red blood cells in the blood is decreasing does that make sense so that's the first thing and it's called a physiologic it's called a physio physiologic physiologic anemia because it's a part of normal pregnancy physiology now another thing that can happen is a true anemia or a pathological process not a physiologic process but a pathological process in which there's an actual decrease in the number of blood cells so here and we're not talking about concentration we're talking about a decrease in the actual number of red blood cells most commonly that anemia and the true anemia is due to a shortage of iron in the body so iron is used to make hemoglobin it's an essential part of hemoglobin and red blood cells are basically packets of hemoglobin so no iron means no red blood cells it's kind of like if you're gonna go make chocolate chip cookies and you want to make let's say 100 of them and you have enough of all of the ingredients to make 100 cookies but you only have enough chocolate chips to make 80 cookies so that's what you're going to end up with only 80 chocolate chip cookies so why the shortage of iron why is there a shortage of iron in pregnancy well these women the pregnant women are by definition I guess women of reproductive age right so they were probably menstruating before becoming pregnant and that blood loss that occurs with each menstrual cycle claims some of the body's iron stores so that's one cause for the iron shortage in pregnancy another cause is that in trying to make its own red blood cells the fetus claim some of moms iron stories now iron deficiency is by far the most common cause of anemia in pregnancy so much so that if a woman is a pregnant woman is fine to be anemic she's usually treated with iron supplementation and only and only if that doesn't resolve the anemia if the supplementation doesn't result in emia do we go looking for another cause all right so speaking of other causes it's worth mentioning that folic acid deficiency so deficiency of folic acid right can also less commonly cause anemia and pregnancy as can other causes all the other regular causes of anemia and something that happens particularly in pregnancy is that the lifespan of a red blood cell decreases so the red blood cell doesn't quite live to be 120 days old before dying and this further contributes to the anemia that we tend to see in pregnancy so I I want to make the point that anemia isn't a problem that's unique to pregnant and you probably already know that but anemia does have some unique implications in pregnancy that it doesn't have in other people for example it can it can lead to things such as a reduction in amniotic fluid levels in the fetus right it can cause concerning fetal heart tones or fetal heart tracings it can lead to spontaneous abortion low birth weight of the fetus and even death of the fetus so so it can be a pretty serious problem in pregnancy now there's another important change that occurs in the blood system of the mom during pregnancy and that is that pregnancy is a hyper is a hyper hyper coagula ball / coagula ball hypercoagulable state so that is to say that the clotting mechanisms in blood are running an overdrive during pregnancy so blood clots really easily and this is primarily because in pregnancy there's an increase in the production of clotting factors so factors such as thrombin and fibrin engine and other clotting factors are made more and there's there's a lot of thought that perhaps this occurs to protect the mother from excessive bleeding during delivery especially the bleeding that occurs when the placenta separates from the uterus so so maybe this is all meant to be protected the problem is is that sometimes you can have too much of a good thing and you end up with blood clots most commonly in the deep veins of the legs and some of that some of that actually has to do with the fact that the enlarging uterus puts pressure on the inferior vena cava and the veins of the legs and that causes blood to pull in the lower extremities which is actually why pregnant ladies almost always complain of swollen legs anyways this pooling of blood in the legs can lead to blood clots and those blood clots are called deep vein they're called deep vein deep vein thrombosis deep vein thrombosis or Moses just means clot so in fact the risk of having a deep vein thrombosis is increased by five fold and pregnancy and it's important to know because the clot in the legs can break off and it can travel to the lungs leading to a pulmonary embolus and up to 40 percent of cases in which you have a DVT which is dangerous and potentially fatal to the mom so when the presence of a DVT or any any clot or thromboembolism of that for that matter is confirmed the woman is put on anticoagulant therapy right away so those are just a couple of the very important changes that occur in the blood system of a pregnant woman