Iron deficiency anemia in pregnancy

Introduction to pregnancy with iron deficiency anemia Irondeficiency anemia (IDA) is the most common anemia in pregnancy, accounting for about 95% of gestational anemia. The main cause of iron deficiency anemia in pregnancy is the increased demand for iron, insufficient iron reserves in pregnant women, insufficient iron intake in food and diseases before and after pregnancy, and will bring to pregnant women and fetuses after iron deficiency anemia. Different degrees of impact, severe anemia is easy to cause perinatal and maternal death, should be highly valued. basic knowledge The proportion of illness: this common disease in women during pregnancy, the incidence rate is about 5%. Susceptible population: pregnant women Mode of infection: non-infectious Complications: edema, congestive heart failure, hypertension, premature delivery, fetal growth restriction, iron deficiency anemia

Pregnancy with iron deficiency anemia

(1) Causes of the disease

1. Increased iron requirement during pregnancy This is the most important cause of iron deficiency in pregnant women. The blood volume during pregnancy is increased by 1300-1500ml. If the blood is 0.5mg per milliliter of blood, iron is needed due to increased blood volume. 650 ~ 750mg, in addition, the placenta, fetal growth and development requires a total of 250 ~ 300mg of iron, so the total amount of iron needed to increase the total amount of iron during pregnancy is 3 ~ 4mg / d in the second trimester, 6 ~ 7mg / d in the late pregnancy, The iron delivered to the fetus through the placenta is 0.4 mg/d in the second trimester and can be increased to 4-7 mg in the full-term pregnancy, while the iron requirement is more pronounced in twin pregnancies.

2. Insufficient reserve iron in women's body Generally, the total iron content in normal adult males is about 4g, with an average of 500mg/kg, while a healthy medium-sized young woman is 2~2.5g, with an average of 350mg/kg, many women. Due to the lack of menstruation during pregnancy, insufficient iron intake in food, multiple pregnancy and breastfeeding factors, the reserve iron in the body is obviously insufficient. In fact, many women have less than 100 mg of available iron.

3. The intake of iron in food is not enough. The iron in food is 10~15mg/d, and the iron that can be absorbed is only 5%~10%. Therefore, the iron that can be absorbed from food is only 1~1.5mg per day. By the end of pregnancy, as the body's demand for iron increases, the absorption rate of iron can increase by 40%, but it still can not meet the needs of pregnancy, not to mention the nausea, vomiting, poor eating, gastrointestinal dysfunction in early pregnancy. Lack of stomach acid, malnutrition, and insufficient protein in food may affect the absorption of iron in the intestines.

4. Pre-pregnancy and post-pregnancy diseases such as chronic infection, parasitic diseases, liver and kidney diseases, hypertensive disorders of pregnancy, prenatal and postpartum hemorrhage, etc., can cause iron storage, utilization and metabolic disorders, iron demand or Loss too much can also affect the process of red blood cell production or the treatment of anemia.

(two) pathogenesis

Due to the growth of the fetus and the increase of blood volume during pregnancy, the need for iron increases, especially in the second half of pregnancy, pregnant women have insufficient iron intake or malabsorption, and are prone to iron deficiency anemia. Severe anemia is easy to cause perinatal and maternal Death should be highly valued.

1. Mechanism of iron deficiency during pregnancy Iron is an essential element of the human body and is the main raw material for the production of hemoglobin. The total amount of iron in normal adult women is about 2g, mainly in the form of combination, accounting for about 65%, and the remaining 35% are iron. Protein, myoglobin, cytochrome and peroxidase exist in the form of available storage iron of about 20%. According to the information published by WH0, many women have insufficient iron intake during non-pregnancy, so they can be used during pregnancy. The storage iron is only about 100mg.

2. The effect of anemia on pregnancy

(1) The impact on pregnant women.

(2) Effects on the fetus: The bone marrow and fetus of the pregnant woman are the main receptor tissues of iron. In the process of competing for the intake of serum iron in pregnant women, fetal tissue predominates, while iron passes through the placenta and is transported in one direction. Direction reversal of transport, under normal circumstances, fetal iron deficiency is not too serious, but when pregnant women with severe anemia (Hb <50g / L), due to placental oxygen and nutrient deficiency, causing fetal growth retardation, fetal distress, premature delivery Or stillbirth.

Pregnancy with iron deficiency anemia prevention

Wang Yuezeng et al. (1984) showed that if normal pregnant women did not add iron, 76.8% of pregnant women's serum ferritin decreased to the level of iron deficiency anemia after 28 weeks of gestation. After correcting the factors of hemodilution, there are still 61 % is in the state of no reserve iron, indicating that the lack of iron in the late pregnancy is common. Inevitably, if it is properly supplemented from the second trimester, the iron deficiency in pregnant women will be significantly improved. Therefore, domestic and foreign experts agree that after 20 weeks from pregnancy, Regular iron supplementation for all pregnant women, even pregnant women with normal diet and nutritional intake, can be oral ferrous sulfate 0.3mg 1-2 times / d, or use other reliable iron supplements during pregnancy, Li Congrong et al (2000) A survey of 587 women found that recessive iron deficiency accounted for 60.1%. The existence of subclinical iron deficiency that has not yet occurred in this anemia should be highly valued during pregnancy, with a view to correcting it in time.

Pregnancy with complications of iron deficiency anemia Complications edema congestive heart failure hypertension premature fetal growth restriction iron deficiency anemia

1. Severe anemia can be combined with severe pregnancy edema, shortness of breath after activity, and even anemia heart disease and congestive heart failure.

2. Concurrent hypertensive disorder complicating pregnancy, premature delivery, fetal growth restriction and stillbirth, severe iron deficiency anemia can have a potential impact on fetal iron supply, and high incidence of preterm birth and pregnancy complications, perinatal The mortality rate is higher.

Pregnancy with iron deficiency anemia symptoms Common symptoms Iron deficiency anemia pale pale fatigue tinnitus dizziness loss of appetite edema diarrhea ascites bloating

1. The storage of recessive iron deficiency is reduced, but the number of red blood cells, hemoglobin content, serum ferritin are in the normal range, and there is no clinical anemia.

2. Early iron deficiency anemia and iron deficiency continue to develop, resulting in a decrease in the amount of red blood cells, but there is still a sufficient amount of hemoglobin in each red blood cell, that is, "positive red blood cell anemia", clinically mild symptoms of mild anemia such as skin, The mucous membrane is slightly pale, tired, weak, hair loss, nail abnormalities, glossitis, etc.

3. Severe iron deficiency anemia lacks iron, bone marrow red blood cells can be completely deficient in iron, bone marrow hematopoiesis is obviously disordered, red blood cell count is further reduced, and each red blood cell cannot obtain enough iron to synthesize hemoglobin, resulting in low pigment red blood cell count Increased, that is, "small cell hypochromic anemia", manifested as pale, edema, fatigue, dizziness, tinnitus, palpitation, shortness of breath, loss of appetite, abdominal distension, diarrhea and other typical symptoms, or even with ascites.

Examination of pregnancy with iron deficiency anemia

1. Peripheral blood hemoglobin <110g / L, blood smear typical small cell hypochromic anemia, red blood cell mean volume (MCV) <80fl (80m3), red blood cell mean hemoglobin content (MCH) <28pg, red blood cell mean hemoglobin concentration (MCHC) <30%, reticulocytes are normal or reduced, and there are no special changes in white blood cells and platelets.

2. The bone marrow is active in the red blood cell system. In the middle and late red blood cell hyperplasia, the red blood cell division is visible, and there is no stainable iron. The young red blood cells in each stage are small in size, less cytoplasm, and the staining is deeper than normal. Polychromatic, irregular edges, small and dense nuclei, no significant changes in granulocyte and megakaryocyte systems.

3. Serum iron <10.74mol/L (60g/dl), total iron binding capacity>53.7mol/L (300g/dl), iron saturation is significantly reduced to below 10%~15%, when Hb is not obvious, The reduction of serum iron is an important early manifestation of iron deficiency anemia.

4. Ferritin examination serum ferritin <14g / L.

According to the condition, the symptoms and signs of clinical manifestations are selected to be B-ultrasound, electrocardiogram, and biochemical examination.

Diagnosis and diagnosis of pregnancy complicated with iron deficiency anemia

diagnosis

Iron deficiency anemia is mainly based on laboratory tests, such as Hb <100g / L, hematocrit <30% suggest anemia, the typical peripheral blood of iron deficiency anemia is:

1. Peripheral blood is small cell hypoglycemia Anemia Hb reduction is more obvious than red blood cell reduction, red blood cell mean volume (MCV) <80/fl, red blood cell mean hemoglobin content (MCH) <28pg, red blood cell mean hemoglobin concentration (MCHC) <30%, Reticulocytes are normal or reduced.

2. Ferritin <14g/L.

3. Serum iron <10.7mol/L (60g/dl), iron binding capacity increased, and transferrin saturation decreased. When hemoglobin was not significantly reduced, serum iron decreased to an early stage of iron deficiency anemia.

4. The bone marrow can stain the iron, the bone marrow shows the red blood cell system hyperplasia, the cell classification sees the young red blood cells; the young red blood cells are relatively reduced, indicating that the bone marrow reserve iron is decreased, and the hemosiderin and iron particles are reduced or disappeared.

Iron therapy is given to pregnant women with iron deficiency anemia. Hematology reflects an increase in the number of reticulocytes, and the rate of increase in Hb varies greatly, but it is usually lower than that of non-pregnant women, mainly related to the specific volume of red blood cells and the difference in blood volume. .

Differential diagnosis

Clinically, it should be differentiated from megaloblastic anemia, aplastic anemia and Mediterranean anemia. According to the history and clinical manifestations, as well as the characteristics of blood and bone marrow, the general differential diagnosis is not difficult, but sometimes several anemias occur. At the same time, comprehensive analysis and judgment must be carried out in order to formulate a reasonable treatment policy.

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