One of the factors that are controlled during pregnancies, with the analytical ones, is that of the amount of iron of the future mother.
Most of the time the hemoglobin concentration falls below 11 g / dl and many professionals consider this decrease as an anemia supplementing the pregnant women 's diet with iron.
The reality is that this supplement manages to increase iron levels (which is what is sought), but according to the hemoglobin levels that are reached increases the risk that the delivery is premature and that the baby is born with low weight.
In other words, the iron supplement given to many pregnant women almost by protocol is contraindicated most of the time. Pregnancy produces various changes in women that must be taken into account. The volume of blood plasma increases producing hemodilution (there is more fluid and the blood is more fluid, less dense, to be able to pass more easily to the placenta and vice versa).
When this phenomenon occurs in blood tests, a decrease in hemoglobin can be seen despite the fact that there are actually more hemoglobin. That is, the woman has more hemoglobin than before she was pregnant, but with increasing plasma volume there is a lower concentration (with which the value of the tests is not entirely true).
Iron needs in pregnancy increase from 1-2.5 mg / day at the beginning to 6.5 mg at the end of pregnancy. This may suggest that they need to ingest more iron, however a balanced diet is enough since this increase in requirements is compensated with a greater capacity for iron absorption. At 12 weeks gestation the absorption capacity increases up to 7% and at week 36 it reaches an incredible 66%.
With all this information we can deduce that supplementation is not necessary. But we go further, because not only is it not necessary, but it has been shown that women with higher hemoglobin levels have more premature births and their babies are born with lower weight.
In a study carried out in London where the data of 153.602 births were analyzed and taking as average hemoglobin value the lowest of the levels obtained in the different analytics it was concluded that the weight of the fetus at birth is related to the fall in the levels of hemoglobin concentration.
According to the study, the risk increase appears when, in the last weeks of pregnancy, the hemoglobin concentration remains above 10.5 g / dl.
In the following graph (which is part of the aforementioned study) we can see the relationship between the weight of newborns and the hemoglobin concentration of mothers. The concentration is expressed in g / l instead of g / dl as we are used in Spain. It is enough to divide the value of the graph by 10 to obtain the data in dl (a value of 85 is equivalent to 8.5 that we usually talk about).
As you can see from 10.6-11.5 g / dl, the number of children born under 2,500 kg begins to increase.
In this other graph that we see below, we can see how higher hemoglobin values are related to an increase in preterm births (thus considering, for the study, those produced before the 37th week of gestation).
As in the previous graph, from 10.6-11.5 g / dl increases the risk, in this case, of having premature children.
Similarly, if hemoglobin drops by 9.6 g / dl the risks also increase. This means that it does not hurt to control and diagnose a possible anemia in pregnancy if the values fall below those 9.6 g / dl, but for this, more specific tests must be carried out with which the values of erythrocytoprotoporphyrin, transferrin saturation and serum ferritin are determined.
Concluding. The lowering of hemoglobin in blood tests is normal and in fact necessary, as it means that the blood itself is changing to be able to reach the baby more easily.
Many professionals see an anemia where there is none and supplement women with iron to avoid possible risks when what they are getting, precisely, is increase the chances of having a premature and low birth weight.
In other words, when you try to fix something that is going well, what you usually get is that it starts to fail.
After reading this study I took the analysis of the second pregnancy of my wife, with a premature delivery in the 35th week of gestation, whose diet had been supplemented with iron and I observed that his hemoglobin upon admission (he was tested) was 14.7 g / dl, the highest value of the graphs that I have shown you (the first pregnancy was at term with a hemoglobin of 12 g / dl).
Will it be the cause of Aran's prematurity? We will never know and almost prefer not to know, but I have something clear: for again we already know.
