Pregnancy sure entails many physical changes, and it is no surprise that growing a baby is hard work that alters your body's needs. But did you know that your blood volume increases quite a bit when you are expecting a baby?
The average healthy woman with an uncomplicated pregnancy will see a 50 percent increase in plasma, while the red blood cell volume goes up less this increase will be somewhere between 20 and 30 percent. Blood volume gradually increases over the course of a pregnancy, reaching its maximum at 34 to 36 weeks, which is just before the end of the pregnancy. A pregnant woman's heart rate, meanwhile, goes up by around 15 beats per minute right during the first trimester.
Besides blood volume increasing, blood also becomes more prone to clotting during pregnancy, because of the liver is doing overwork to produce coagulation factors. This thrombosis is most likely to strike the left leg.So, why these changes? And why does the make-up of a pregnant woman's blood changes along with the amount of blood she has in her body? According to scientists, the great increase in plasma volume helps cope with a large boost in blood flow to the kidneys and skin. Those organs don't need a lot of extra oxygen, so red blood cells don't become all that much more numerous while a woman is expecting a baby.
It's fascinating to note that moms who have a larger baby, carry twins or triplets, or who have already had a few kids before, gain more blood during pregnancy than others. The extra blood helps cushion the baby, according to some. It also gives you a reserve in case you lose a significant amount of blood during labor and delivery.
The extra blood that you get is there to meet the additional demands on your body caused by your pregnancy. Some women wonder if the increase has something to do with the baby's blood. The answer is that the baby's blood circulation is a system completely separate from the maternal system, and that the fetus' blood is not included in the 50 percent increase.