Megaloblastic anemia in pregnancy

Introduction to pregnancy with megaloblastic anemia Megaloblasticanaemia, also known as nutritional megaloblastic anemia, is rare in clinical practice, accounting for 7% to 8% of all anemia. There are cases all over the world. Most of them occur in northern areas such as Shanxi and Shaanxi. The main cause of malnutrition is not only affecting hematopoiesis, but also involving nerves, digestion, circulation, immunity and endocrine system. It is characterized by systemic diseases and pregnancy. Young red blood cell anemia is more common, accounting for 43.2% of all giant anemia. basic knowledge The proportion of sickness: 0.01% Susceptible population: pregnant women Mode of infection: non-infectious Complications: jaundice, diarrhea, constipation

Pregnancy with megaloblastic anemia

(1) Causes of the disease

The disease is mainly caused by malnutrition of folate deficiency, and is rarely caused by vitamin B12 deficiency.

Folic acid and vitamin B12 are important coenzymes in the process of synthesizing DNA. Folic acid itself is inactive. Coenzyme is tetrahydrofolate. Tetrahydrofolic acid is produced by the action of dihydrofolate by folate reductase. Its nature is very unstable. It is easy to be oxidized, so the disease can occur when the formation of tetrahydrofolate can prevent the metabolism of folic acid. When it is lacking, it can make DNA synthesis disorder, and various tissues of the whole body can be affected, but the hematopoietic tissue is the most serious. Young red blood cells proliferate and mature, and megaloblasts with abnormal morphological and functional appearance in the bone marrow. These abnormal megaloblasts have a shorter life span than normal and are often prematurely destroyed, which is also a factor causing anemia.

1. The cause of folate deficiency during pregnancy.

2. The cause of vitamin B12 deficiency during pregnancy is mainly due to the decrease of intracellular secretion factors in the gastric mucosal wall, leading to the absorption of vitamin B12, and the large amount of fetal needs, leading to the megaloblastic anemia of vitamin B12 deficiency.

3. The effect of megaloblastic anemia on pregnant women and fetuses.

(two) pathogenesis

Folic acid and vitamin B12 are important coenzymes in the process of DNA synthesis in the nucleus. When they are deficient or metabolically disordered, DNA synthesis is impaired, and various tissue cells can be involved in the whole body, but the hematopoietic tissue is the most serious, especially the erythroid cells. Because nuclear maturation is delayed, nuclear division is blocked, nuclear development and maturation lag behind cytoplasm, and there are a large number of immature red blood cells in various stages of morphological and functional abnormalities in the bone marrow. These abnormal megaloblasts have shorter life span than normal red blood cells and often die prematurely. This causes anemia. In addition, granulocytes and megakaryocytes can also have morphological changes and a decrease in the number of mature cells. Non-hematopoietic tissues such as gastrointestinal mucosal cells also show delayed nuclear maturation, causing gastrointestinal dysfunction and malabsorption. Vitamin B12 is not only a substance necessary for biosynthesis of nucleic acids and proteins, but also a coenzyme necessary for hemoglobin synthesis. It also participates in the biochemical process of folic acid in the body, and demethylation of methyltetrahydrofolate to tetrahydrofolate directly affects DNA and RNA synthesis, therefore, in the process of megaloblastic anemia, folic acid and vitamin B12 Influence, closely related, plays an important role.

Pregnancy with megaloblastic anemia prevention

1. Pay attention to nutrition during pregnancy, eat more fresh vegetables containing folic acid, animal protein and so on.

2. Prevent infections, especially intestinal infections, to reduce factors that are not conducive to folic acid absorption.

3. In the previous pregnancy, megaloblastic anemia occurred, and it is easy to re-emerge after the next pregnancy. Therefore, folic acid should be taken early, 5 mg twice a day.

4. Stop drugs that affect folate metabolism: such as birth control pills, antiepileptic drugs (phenytoin), ethanol, etc.

5. Foreign reports, women who have given birth to a neural tube defect, if the oral administration of 4 mg of folic acid per day in the first trimester, the possibility of abnormalities is reduced, Czeizel et al reported that daily supplementation of folic acid 0.8mg can increase the chance of pregnancy, therefore advocates all the childbearing age Women are given at least 0.4 mg of folic acid per day.

6. Eat more fresh vegetables, fruits, melons, meat, animal liver and kidneys during pregnancy.

7. Oral folic acid 5mg per day, or folic acid 10 ~ 30mg once / d, intramuscular injection until the symptoms disappear, if the treatment effect is not ideal, should check for iron deficiency, can also add iron.

8. Vitamin B12 100mg, intramuscular injection, 1 time / d, a total of 2 weeks, later changed to 2 times a week, until hemoglobin returned to normal, with neurological symptoms, folic acid alone may make the nervous system symptoms worse, should Attention.

9. If the hemoglobin is <60g/L, fresh blood or concentrated red blood cells can be intermittently transferred.

10. During childbirth, avoid prolonged labor, prevent postpartum hemorrhage, and prevent infection.

Pregnancy with complications of megaloblastic anemia Complications jaundice diarrhea constipation

Complications of pregnancy with megaloblastic anemia often have pale, fatigue, decreased endurance, dizziness, palpitations and other anemia symptoms. In severe cases, whole blood cells are reduced, repeated infections and bleeding. A small number of patients may have mild jaundice. Oral mucosa, tongue nipple atrophy, tongue surface is "beef-like tongue", can be associated with tongue pain. Gastrointestinal mucosal atrophy can cause loss of appetite, nausea, bloating, diarrhea or constipation. VitB12 deficiency has depression, insomnia, memory loss, paralysis, hallucinations, delusions and even mental disorders, personality abnormalities.

Pregnancy with megaloblastic anemia symptoms Common symptoms Fatigue loss of appetite, weakness, weakness, edema, dizziness, dizziness, low fever, nausea, numbness

In addition to the general anemia symptoms, it has the following characteristics:

1. It occurs mostly in the third trimester of pregnancy, about 50% occurs after 31 weeks of pregnancy, and the rest occurs in the puerperium; it is usually around 30 years old, more than maternal women, more than singleton, and 25% of patients in the next pregnancy Easy to re-issue.

2. Acute onset, anemia is moderate or severe, mostly manifested as dizziness, fatigue, weakness, systemic edema.

3. Symptoms of digestive tract are obvious, 1/2 patients have nausea, loss of appetite, vomiting and diarrhea, 1/3 of patients have pain in the tongue and lips, acute pain occurs at the tip of the tongue and tongue, and the tongue is bright red. The tongue can appear as a bloody vesicle or a shallow ulcer, and the tongue nipple shrinks into a "light tongue."

4. Due to the lack of vitamin B12 can cause peripheral neuritis, manifested as fatigue, hand and foot numbness, sensory disturbances, difficulty walking and other neurological symptoms such as peripheral neuritis and subacute or chronic spinal cord posterior bundle combined lesions.

5. The effect on pregnancy, such as timely treatment of better prognosis; if not treated in time, severe cases can cause miscarriage, premature delivery, placental abruption, fetal growth restriction, stillbirth and other complications, often accompanied by vomiting, edema, high blood pressure, Proteinuria; anemia in the puerperium period, more than the first week after delivery, due to the lack of folic acid on the basis of the lack of folic acid in the lactation period, if not timely supplementation often induce anemia symptoms, there is a significant bleeding and infection tendency, fetal nerve The incidence of tube malformation increased significantly.

The clinical symptoms of folic acid and/or vitamin B12 deficiency, bone marrow and blood changes are similar, but vitamin B12 deficiency may have neurological symptoms, while folic acid deficiency has no neurological symptoms.

Examination of pregnancy with megaloblastic anemia

Peripheral blood

It is helpful for the diagnosis of acute typical cases. The earliest peripheral blood smear shows excessive neutrophil lobulation, and 5 to 6 leaf nucleus can be seen. As the anemia is aggravated, the erythrocyte size and shape are different in the smear. Large red blood cells, red blood cell volume is larger than normal, and even if the anemia is severe, immature red blood cells can be seen. With the lack of folic acid in the mother and the anemia increase, the white blood cells or platelets also decrease or both decrease.

Mild patients with atypical blood, especially when coexisting with iron deficiency anemia, the newly formed red blood cells can not estimate the average cell volume (MCV), and thus may be normal red blood cells, easy to regenerate when white blood cells and thrombocytopenia are significant Obstacle anemia is confused.

2. Bone marrow

The erythroid cell line is megaloblastic hyperplasia, and the megaloblasts at different maturity stages can account for 30% to 50% of bone marrow nucleated cells.

3. Biochemical examination

1 serum folic acid <3ng / ml, red blood cell folic acid <100ng / ml, indicating folic acid deficiency.

2 serum vitamin B12 <90pg / ml; radioimmunoassay vitamin B12 absorption test <7% can be diagnosed as vitamin B12 deficiency.

Diagnosis and differentiation of pregnancy with megaloblastic anemia

1. This disease occurs mostly in the third trimester, with severe anemia, often feeling weak, dizziness, palpitations, shortness of breath, pale skin mucous membranes, diarrhea, glossitis, nipple atrophy, etc., low fever, edema, splenomegaly, and apathy are also common.

2. Nervous system symptoms such as numbness, acupuncture, icyness, and difficulty in walking due to peripheral nerve degeneration.

3. Laboratory examination.

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