Anemia is a relatively common comorbidity in pregnancy, and the World Health Organization criteria for anemia are that hemoglobin <110 g/L is diagnosed as pregnancy-associated anemia. It can increase the risk of hypertensive disorders in pregnancy, premature rupture of membranes and puerperal infections in the mother and fetal growth restriction, fetal hypoxia, stillbirth, stillbirth and preterm delivery in the fetus. What are the causes of anemia during pregnancy? How to treat and prevent it? Let's talk about this topic today.
I. Causes of anemia during pregnancy
1. Iron deficiency anemia.
① is the most common type of anemia during pregnancy, accounting for about 95% of anemia during pregnancy.
②Increased iron requirement during pregnancy is the main cause of iron deficiency anemia in pregnant women. The increase in blood volume during pregnancy requires 650-750mg of iron, and fetal growth and development requires 250-350mg of iron, so the total requirement of iron during pregnancy is about 1000mg.
③ Pregnant women need at least 4mg of iron per day, and only 1-1.5mg of iron is provided in the daily diet. Therefore, if no additional iron supplement is given, iron deficiency anemia is likely to occur during pregnancy.
2. Megaloblastic anemia.
①The incidence is reported to be about 0.8% in China, and it is anemia caused by impaired DNA synthesis caused by folic acid or vitamin B12.
②Megaloblastic anemia during pregnancy is 95% caused by folic acid deficiency, and a few develop due to vitamin B12 deficiency.
(③Insufficient sources or malabsorption: Folic acid and B12 are mainly found in plant or animal foods. Insufficient intake of green leafy vegetables, legumes and animal proteins can cause the disease. Chronic gastrointestinal diseases affecting the absorption of both can also cause the disease.
④Increased need during pregnancy: normal adult women need 50-100 μg of folic acid per day, while pregnant women need 300-400 μg per day.
⑤ Increased excretion of folic acid: increased renal blood flow in pregnant women, increased filtration of folic acid in the kidney and decreased absorption by the renal tubules.
3. Aplastic anemia.
①It is a syndrome caused by hematopoietic disorder due to the decrease in the quantity and quality of bone marrow hematopoietic stem cells, resulting in a decrease in blood trisomy as a manifestation.
②According to the statistics, the combined reangiogenesis in pregnancy accounts for 0.3%-0.8% of the total number of deliveries.
③The etiology of reoccurrence is complicated, and half of them are primary reoccurrence of unknown cause.
④Pregnancy is not the cause of reoccurrence, but pregnancy can aggravate the original disease. A small number of women develop the disease during pregnancy, remit after delivery, and relapse when they are pregnant again.
Treatment of anemia during pregnancy
1.Iron deficiency anemia
①Treatment principle: supplementation of iron and removal of the causes of iron deficiency anemia.
②Oral iron: pregnant women with iron deficiency anemia should take 100-200mg of elemental iron daily, and recheck the hemoglobin after 2 weeks of treatment to assess the efficacy, usually the hemoglobin level increases by 10g/L after 2 weeks and 20g/L after 3-4 weeks.
h iron is recommended to be taken together with vitamin C to increase iron absorption.
(Image source: Guidelines for the diagnosis and treatment of iron deficiency and iron-deficiency anemia in pregnancy, Chinese Journal of Perinatal Medicine, Vol. 17, No. 7, July 2014)
(③Injectable iron: those who cannot tolerate oral iron or whose oral iron is ineffective may opt for injectable iron. Iron injections can restore iron stores more quickly and raise hemoglobin levels. The formula for calculating the dosage of injectable iron is as follows: total injectable iron dose (mg) =
Body weight (kg) × (hemoglobin target value – actual hemoglobin value) (g/L) × 0.24 + stored iron (mg); stored iron = 500 mg.
(Image source: Guidelines for the diagnosis and treatment of iron deficiency and iron-deficiency anemia in pregnancy, Chinese Journal of Perinatal Medicine, Vol. 17, No. 7, July 2014)
④Blood transfusion: transfusion of concentrated red blood cells is one of the most important treatments for severe anemia. blood transfusion is recommended for those with Hb<70 g/L.
2.Megaloblastic anemia
①Folic acid supplementation: pregnant women with megaloblastic anemia should take 15 mg of folic acid orally or 10-30 mg of folic acid intramuscularly once a day until symptoms disappear and anemia is corrected. If the effect of treatment is not significant, the presence of iron deficiency should be checked and iron supplements can be given at the same time.
②B12 supplementation: Vitamin B12 100-200μg intramuscular injection once daily for 2 weeks. Later change to twice a week until hemoglobin returns to normal.
③For those with neurological symptoms, folic acid alone may aggravate the neurological symptoms, and B12 should be supplemented in time.
3.Aplastic anemia
①There is no special treatment for combined aplastic anemia in pregnancy, and supportive treatment is the main treatment.
② Contraception should be used until the condition is in remission. If you are pregnant, abortion should be performed at the same time as blood transfusion.
③In the middle and late stages of pregnancy, because of the greater risk of termination of pregnancy, supportive treatment should be strengthened to ensure that the pregnancy is delivered at full term as far as possible.
④Close supervision, rest, nutrition, intermittent oxygenation, small amount of intermittent and multiple transfusions should be carried out during pregnancy to improve the whole blood cells and make the hemoglobin more than 60g/L to ensure the safety of mother and child.
Prevention of anemia during pregnancy
1. Iron deficiency anemia
① Actively treat the related diseases that can lead to iron deficiency anemia before pregnancy to increase the iron reserve.
②Enhance nutrition during pregnancy and consume more iron-rich foods, such as pig liver, chicken blood, beans, kelp, fungus and nori, etc.
③During prenatal checkups, pregnant women must have regular blood tests, which should be repeated especially in pregnancy.
④It is recommended that pregnant women with serum ferritin <30μg/L should take oral iron supplementation
⑤The incidence of iron deficiency anemia is not high before 20 weeks of gestation, and increases significantly in the second trimester, especially at the full term of pregnancy. Numerous studies have shown that appropriate iron supplementation from 20 weeks of gestation can significantly improve iron deficiency in pregnant women, so all pregnant women should take iron supplementation routinely.
(6) Preventive medicine should be used according to the recommended amount. Increasing the amount of medicine does not improve the efficacy, but will increase the gastrointestinal side effects.
2.Megaloblastic anemia
①Change poor dietary habits and consume more fresh vegetables, fruits, melons and beans, meat, animal liver and kidney.
②For pregnant women with high-risk factors, folic acid 0.5-1mg should be taken orally daily for 8-12 weeks starting from the third month of pregnancy.
③Vitamin C plays an important role in the synthesis of tissue collagen, absorption of iron and metabolism of folic acid. The recommended supply of vitamin C for pregnant women in China is increased from 60mg to 80mg per day for non-pregnant women. vitamin C should be appropriately supplemented during pregnancy.
3.Aplastic anemia
① Chemical substances, especially drugs, are the most common factors leading to aplastic anemia, so attention must be paid to the rational use of drugs. Avoid the application of chloramphenicol, sulfonamides, etc., as much as possible, and avoid exposure to harmful chemicals such as benzene.
②Viral infections are closely related to the development of aplastic anemia, the most common ones are hepatitis virus and microvirus B19, attention should be paid to prevent the possibility of infection with these viruses.