Feeling tired during her pregnancy, especially towards the end, it's pretty normal and that's explained! Working for two is an effort that mobilizes the whole organism.
1. During pregnancy, blood circulation precipitates its flow
- Blood flow changes at the beginning of pregnancy. The network of arteries and veins in the wall of the uterus is reorganized to respond to placental exchanges that create new needs. The blood volume increases regularly to reach its maximum (+ 40%!) Around the 32nd week of pregnancy.
- The heartbeat accelerates, one records on average 10 to 20 additional pulsations per minute (which brings the pulse to 80 or 90 at the end of pregnancy). An acceleration quite normal since the heart must "pulse" up to 6 liters of blood per minute instead of the usual 4 liters.
- This increase in blood flow is accompanied by a drop in blood pressure. This is explained by the dilation of the venous walls, which gives the blood much larger ducts, and thus facilitates the blood circulation. This vasodilatation can also promote the appearance of oedemas or varicose veins.
- After birth, it will take about a month and a half before the "hemodynamic" values (flow, heart rate, blood pressure ...) return to the pre-pregnancy stage.
2. Respiration side, we must give a second breath
- Pregnancy causes an increase of about 20% in oxygen consumption, mainly for the needs of the fetus. To ensure this additional contribution, the expectant mother does not breathe really faster than usual, but differently.
- Embarrassed by the growing proportions of the uterus, the muscles of the abdomen work less, the breathing is no longer from the "belly" but "chest", causing a deeper breathing to absorb the lungs a volume of air most important.
- Often follows a feeling of "lack of air". Fatigue is felt more easily, hence the need for more care.
3. Iron, calcium, vitamins ... nutrients struggle to suffice
- The fetus must be able to have not only energy, but also calcium, iron, vitamins ... construction materials essential for its growth and that it draws, without qualms, in maternal reserves that can end up seriously damaged or even exhausted. Again, fatigue is at the rendezvous and some contributions may need to be supplemented (with doctor's agreement) with tablets, especially for iron, calcium and vitamins D and B9 (the precious folates ).
4. Pregnancy, a tour de force for the kidneys
- To ensure the workload imposed by pregnancy, the size of each kidney of the future mother increases by one centimeter, but it is not enough. They suffer the immediate backlash of the transformation of the blood circulation. As the quantity of blood passing through them increases considerably, they must rid it of not only maternal waste, but also that which the fetus rejects. By the 10th week, the kidneys are running at full speed. If they find themselves overwhelmed, they produce hormones to accelerate the blood flow, which helps them in their mission of purification. In return, this increased blood pressure can cause fatigue and hypertension. The latter will be monitored to avoid any risk of toxemia of pregnancy.
5. On the pancreas side, it's the great upheaval
- During pregnancy, energy needs increase: 15% on average during the last quarter. But the body is no longer quite the same use of the nutrients that are provided. It is the pancreas (a gland located between the duodenum and the spleen) that produces insulin, a substance giving the blood the order to assimilate glucose. In the first months of pregnancy, the cells of the pancreas begin to grow, increasing the insulin level in the mother's blood. The body then assimilates more quickly the sugar that is absorbed, which can cause slight "hypoglycemic" discomfort, resulting in vertigo.
- In the second part of pregnancy, reversal of situation! Insulin is thwarted by so-called "antagonistic" hormones. Subjected to contradictory orders, the cells become less sensitive to insulin, whose concentration in the blood must increase a lot (+ 30% in the long run) to maintain the normal level of sugar, thus avoiding the risk of diabetes linked to the pregnancy. As for fats (lipids), their concentration in the blood increases gradually and significantly.
- The return to normal will require several months after delivery.
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