Low Hemoglobin in Pregnancy, What You Need to Know


  • 1 What is hemoglobin 
  • 2 What Happens to Blood in Pregnancy
  • 3 When you have low hemoglobin in pregnancy 
  • 4 When performing blood counts in pregnancy
  • 5 Risk Factors for Low Hemoglobin in Pregnancy
  • 6 Iron deficiency and low hemoglobin in pregnancy
  • 7 Causes of Anemia in Pregnancy 
  • 8 Symptoms of Anemia in Pregnancy
  • 9 Risks of anemia gravidarum
  • 10 What to do against anemia in pregnancy
  • 11 Low hemoglobin in pregnancy and transfusions 

How many of you are part of the ranks of expectant mothers who suffer from anemia and are struggling with the search for foods rich in iron and often with supplements? Know that you are in good company because this is the case for about 40 percent of pregnant women. At the base of the anemia there is a problem of low hemoglobin, as well as a lack of iron, folic acid or vitamin B12. But the solutions are there. 

What is hemoglobin 

Hemoglobin is a protein found in red blood cells. It has a very important task which is to transport oxygen throughout the body, passing through the organs. Oxygen is "captured" by hemoglobin as it passes through the pulmonary capillaries. Then, thanks to the pumping of the heart and blood flow, it reaches all tissues. In the reverse path, it charges carbon dioxide which is deposited in the lungs to be eliminated from the body through breathing. A continuous and fundamental cycle for the human body. 

Normal hemoglobin values ​​depend on various factors, such as the person's weight, age and gender. Women tend to have lower hemoglobin than men. This happens due to the loss of blood that occurs with menstruation. It is important to know if you suffer from low hemoglobin before pregnancy, so that you can immediately prepare the right strategy with your gynecologist to prevent the situation from getting worse.

What Happens to Blood in Pregnancy

As with all the organs and systems of our body, when we are expecting a baby, the cardiovascular system also changes. The blood increases in volume to meet both the needs of the mother and those of the fetus. Keep in mind that the baby absorbs many substances from the mother's organism, including iron. And it is one of the reasons why anemia is so common, almost "physiological". 

With the increase in blood volume, progressive over the trimesters, a phenomenon called hemodilution occurs, which is one of the possible causes of low hemoglobin in pregnancy. In very simple words, the plasma (i.e. the liquid part of the blood) increases and the corpuscular part (red blood cells) is more diluted. There is therefore a reduction in the blood concentration of red blood cells and hemoglobin is lowered. 

When you have low hemoglobin in pregnancy 

Generally speaking, a woman (pregnant or not) should have a hemoglobin value of 12,1 to 15,1 g / dl. Below 12 g / dl it is considered anemic. In pregnancy, anemia is diagnosed when the level drops below 10 g / dl. 

To evaluate the hemoglobin trend during the 9 months, the gynecologist regularly prescribes a complete blood count. It is a simple blood test that gives information on blood values, such as the quantity and size of red blood cells, the number of white cells, platelets and so on for all components.

When performing blood counts in pregnancy

The Del Paeseno health service offers expectant mothers some exams for each quarter. Among them, there is also the blood count. It is therefore free: 

  • in the first trimester of pregnancy.
  • In the third trimester of pregnancy between weeks 28 + 0 and 32 + 6 and between weeks 33 + 0 and 37 + 6.

If there are any special conditions (such as extremely low hemoglobin or anemia that does not improve even with supplements), your doctor may recommend that you do the blood count a few more times. 

Risk factors for low hemoglobin in pregnancy

The hemodilution we mentioned above is an absolutely physiological phenomenon that affects all pregnant women. A lowering of hemoglobin can therefore simply be caused by what happens naturally in our cardiovascular system. 

However, some conditions are factors that predispose to low hemoglobin in pregnancy. 

  • Twin pregnancies: iron reserves are attacked by only one fetus. Let alone with two!
  • Uterine fibroids: can cause frequent bleeding. 
  • Hemorrhoids: Just like myomas, they often cause blood loss. 
  • Placenta previa: same thing. 

Iron deficiency and low hemoglobin in pregnancy

Among its many tasks, iron is important for the production of hemoglobin. When it is in short supply, the bone marrow produces lower amounts of hemoglobin. A vicious circle is therefore triggered that leads to anemia, a disorder that, in pregnancy, can have serious consequences for the mother and fetus. 

Iron introduced with food accumulates in the liver in the form of ferritin. When an iron deficiency is to be assessed, ferritin testing is prescribed between blood tests, which indicates how much iron is available. Sideremia is another thing because it indicates the amount of iron circulating in the blood.

Causes of anemia in pregnancy 

  • Hemodilution. 
  • Iron deficiency.
  • Folate deficiency: They also play an important role in the production of red blood cells. Another good reason, in addition to preventing neural tube defects such as spina bifida, to take folic acid regularly at least throughout the first trimester of pregnancy.
  • Vitamin B12 deficiency: This vitamin is also involved in the production of red blood cells. It is found mainly in meat (red and white), eggs, fish, dairy products and cereals. Vitamin B12 deficiency is quite common in vegetarians who therefore need to supplement it by mouth.

Symptoms of anemia in pregnancy

Tiredness, irritability, nervousness, slight dyspnea (difficulty breathing), disturbed sleep, poor mental clarity are the symptoms that often occur when there is an iron deficiency. Always refer them to the gynecologist, never take anything lightly.  

Risks of anemia gravidarum

Excessive iron deficiency is not good for either the mother or the baby in the belly. The risks are:

  • premature birth.
  • Low birth weight.
  • Low iron reserves at birth with more chance of developing anemia in the first year of life.
  • Thyroid dysfunction (especially hypothyroidism).
  • Higher incidence of postpartum depression.

What to do against anemia in pregnancy

To try to combat anemia, it is obviously necessary to first go back to the causes of the disorder. There is little to be done on hemodilution, which involves low hemoglobin in pregnancy. Things change if there is a lack of iron or folate at the root of the anemia. 

Nutrition plays a very important role from this point of view. Foods of animal origin are those that contain the most iron in the form most easily assimilated by the body ("heme"). These include liver and offal in general, meat (turkey, chicken, lean red), fish (for example tuna, cod and salmon), egg yolk. 

Vegetables, on the other hand, mostly have "non-heme" iron which, unlike the previous one, is more difficult to assimilate. To do this, it is necessary to combine particular substances, such as vitamin C. Foods of vegetable origin with higher quantities of iron are legumes, dried mushrooms and fruit, whole grains, dark green leafy vegetables.

Warning: just as there are substances that help the body absorb iron better, there are others that hinder it. For example, foods rich in calcium (such as milk and derivatives), tannins (coffee, tea, cola-based drinks, chocolate), phytates (inhibit the absorption of nutrients). It is therefore understood that their consumption should be avoided when eating foods that contain iron.

Folate is found mainly in vegetables, but cooking significantly reduces their content. In this case or when the iron or vitamin B12 taken with food are not sufficient, it is necessary to take food supplements, respectively of folic acid, iron or vitamin B12. The gynecologist will prescribe them if necessary. 

Low hemoglobin in pregnancy and transfusions 

Even though the blood bags are now super controlled and the risks are minimized, the idea of ​​a blood transfusion probably puts anyone a little agitated. But rest assured: the last ratio is considered, especially in the case of very low hemoglobin (7 g / dl). 

During birth (both natural and caesarean), a certain amount of blood is always lost. If it comes to that time with very low hemoglobin, a transfusion might be needed. For this reason, blood tests are really important in order not to neglect any aspect and for the safety of mother and baby. 

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