The blood circulatory system (cardiovascular system) delivers nutrients and oxygen to all cells in the body. It consists of the heart and the blood vessels running through the entire body. The arteries carry blood away from the heart; the veins carry it back to the heart.The system of blood vessels resembles a tree: The trunk, the main artery (aorta), branches into large arteries, which lead to smaller and smaller vessels.he arteries carry blood away from the heart; the veins carry it back to the heart. The system of blood vessels resembles a tree: The trunk, the main artery (aorta), branches into large arteries, which lead to smaller and smaller vessels.
You probably won't return to your pre-pregnancy weight for some time, but you will lose a significant amount of weight immediately after delivery. Subtracting one 7- to 8-pound baby, about a pound or so of placenta, and another few pounds of blood and amniotic fluid leaves most new moms about 12 pounds lighter.he weight keeps coming off, too. All the extra water your cells retained during pregnancy, along with fluid from the extra blood you had in your pregnant body, will be looking for a way out. So you'll produce more urine than usual in the days after birth â an astounding 3 quarts a day. You may perspire a lot, too.
Weight Gained During Pregnancy. The amount of weight you put on during pregnancy depends on your normal body mass index (BMI), which is determined by dividing your weight in pounds by your height in inches. If this figure is below 18.5 you are underweight, and can expect to gain 28 to 40 lbs.during pregnancy, according to babycentre.co.uk. If your BMI is between 18.5 and 24.9 you are of average weight and should gain between 25 and 35 lbs.f this figure is below 18.5 you are underweight, and can expect to gain 28 to 40 lbs. during pregnancy, according to babycentre.co.uk. If your BMI is between 18.5 and 24.9 you are of average weight and should gain between 25 and 35 lbs.