16-Anemia in pregnancy.pdf

 RBCs count (< 3.5 million/mm3) or ↓↓ Hb level (< 11 gm/dl) or both leading to deficient O2 carrying capacity of blood.  > 50% of all pregnant women suffer anemia during pregnancy.  Aggravation of preexisting anemia due to: 1. ↑↑ maternal plasma volume > RBCs volume leading to hemodilution...

 RBCs count (< 3.5 million/mm3) or ↓↓ Hb level (< 11 gm/dl) or both leading to deficient O2 carrying capacity of blood.  > 50% of all pregnant women suffer anemia during pregnancy.  Aggravation of preexisting anemia due to: 1. ↑↑ maternal plasma volume > RBCs volume leading to hemodilution or hydremia (anemia of pregnancy). 2. Fetal utilization of substrates necessary for building up of Hb molecules. A. Maternal: PIH, placental abruption, abortion, preterm labor, PPH & puerperal sepsis. B. Fetal: IUGR or IUFD.  Hb molecule is formed of 2 parts; heme (iron containing porphyrin) & globin (protein formed of 2 pairs of polypeptide chains).  Adult Hb (Hb A) is formed of 2 α & 2 β chains while fetal Hb (Hb F) is formed of 2 α & 2 γ chains & it has higher affinity for O2 than Hb A. Method of calculation Normal value Hb level (% of normal) ÷ CI (color index) 1 RBCs count (% of normal) MCV (mean corpuscular volume) Hct value ÷ RBCs count 90 μ3 MCH (mean corpuscular Hb) Hb level ÷ RBCs count 30 pg MCHC (mean corpuscular Hb Hb level ÷ Hct value 33 gm/dl concentration)  ① Iron deficiency anemia: Commonest cause of anemia in pregnancy. ↓↓ indices ② Vitamin B6 deficiency anemia. ③ Chronic infection: 3rd most common cause of anemia in pregnancy. ④ Chronic lead poisoning. ⑤ Certain types of thalassemia. ↑↑ indices ① Folic acid deficiency anemia. ② Vitamin B12 deficiency anemia (pernicious anemia). ① Hemorrhagic anemia: 2nd most common cause of anemia in pregnancy & it is due to acute or chronic blood loss in pregnancy. ② Hemolytic anemia: a) Immune hemolytic anemia: 1) Isoimmune: As in incompatible blood transfusion. 2) Autoimmune: As in hepatitis. b) Non immune hemolytic anemia: 1) Intracorpuscular causes (chronic hemolytic anemia): a. Hemoglobinopathies: Unaltered indices 1. Thalassemias: Autosomal recessive disease due to abnormalities in synthesis of α chains (α thalassemia) or β chains (β thalassemia) of Hb. 2. Sickle cell disease: Autosomal recessive disease due to formation of Hb S (by replacement of glutamic acid by valine at position 6 on polypeptide chains of Hb). b. Structural defect in RBCs: As spherocytosis & elliptocytosis. c. Enzymatic defect in RBCs: As G6PD deficiency & pyruvate kinase deficiency. 2) Extracorpuscular causes: As in preeclampsia, prosthetic heart valves & malarial infection. ③ Aplastic anemia: Due to bone marrow suppression.  Anemia due to deficiency of iron stores.  Commonest type of anemia è pregnancy.  Normal daily diet contains 14-15 mg iron but only 10-15% of dietary iron (1-2 mg elemental iron) is absorbed depending on iron stores (ferritin-apoferritin system).  Iron is absorbed in ferrous state in presence of vitamin C.  Phytate & phosphate ↓↓ iron absorption.  Heme iron of red meat & liver is rapidly absorbed than vegetable iron (as in apple & spinache).  During pregnancy, there is extra need of 1000 mg of elemental iron throughout pregnancy: 170 mg: ▪ To compensate for external iron loss. 450 mg: ▪ To allow expansion of maternal cells. 270 mg: ▪ For fetal needs. 90 mg: ▪ For placenta & cord.  This extra need ↑↑ the needed daily absorbed amount to 4 mg of elemental iron (2 mg for adult non pregnant female) & daily requirements to 30-60 mg/day. A. ↓↓ intake: Poor diet or severe morning sickness & vomiting. B. ↓↓ absorption: 1. Vitamin C deficiency. 2. ↑↑ intake of phytates or phosphates. 3. ↓↓ gastric acidity & use of antacids. 4. Malabsorption syndrome. 5. Parasitic infestations. C. ↑↑ requirement: As in multifetal pregnancy or multiparity. D. ↑↑ loss: Due to chronic Hge. ① General: Easy fatigability, fainting, blurring of vision, pallor, glossy tongue & brittle nails. ② Gastrointestinal: Stomatitis, anorexia, nausea, vomiting, flatulence & constipation. ③ Cardiovascular: Palpitation, throbbing, dyspnea, anginal pains, edema LLs, water hammer pulse, accentuation of heart-Changed sounds, ejection murmurs & severe cases may progress to HF. ④ Nervous: Headache, lack of concentration, numbness & tingling. ① Complete blood count (CBC): a) Hb level: ↓↓ b) RBCs: Different sizes (anisocytosis) & different shapes (piklocytosis). c) Reticulocytic count: Normal. d) Leukocytic & platelet counts: Normal. e) Blood indices: ↓↓ ② Blood chemistry: a) Serum iron: ↓↓ b) Serum ferritin: ↓↓ c) Iron binding capacity: ↑↑ d) Free erythrocyte protoporphyrin: ↑↑ ③ Bone marrow biopsy: Shows nucleated RBCs & absent hemosiderin granules. A Proper spacing of pregnancies. B Treatment of any cause of anemia before pregnancy. C Adequate nutrition: ① Good prepregnancy nutrition. ② Eating healthy & balanced diet during pregnancy. D Iron supplementation:  All pregnant women need iron supplementation during pregnancy.  Iron supplementation is usually started after 16 weeks & not before 14 weeks. ▪ 60-80 mg of elemental iron daily which can be obtained from one of the followings: 1) 200 mg ferrous fumarate. 2) 300 mg ferrous sulfate. 3) 550 mg ferrous gluconate. a) 1000 mg vitamin C (to ↑↑ absorption). b) 2 mg folic acid (to ↑↑ hematopoiesis). written ① Oral iron therapy: Indications: Mild anemia & when there is enough time for correction (16- 30 weeks GA). Dose: Triple the prophylactic dose. Response: This treatment is supposed to ↑↑ Hb level by 1 gm/dl/month. Side effects: Gastric upsets, constipation & dark green or black stools. ② Parenteral iron therapy: Indications: a) Severe anemia few weeks before EDD (> 30 weeks GA). b) Intolerance to or ineffectiveness of oral iron therapy. c) GIT disorder retarding absorption of oral iron (as malabsorption syndrome). Calculation of needed dose: By giving 250 mg of elemental iron for each gram of Hb below normal. Routes of administration: IM injection or IV infusion in crystalloid solution.  Response: This treatment is supposed to ↑↑ Hb level by 0.8 gm/dl/week. Side effects: a) Pain & staining at site of injection. b) Hemosiderosis (in cases è overdose). c) Anaphylaxis. Precautions: a) Injection sites should be changed (in cases of IM injection). b) Sensitivity testing must be done before administration (in cases of IV injection). c) Treatment should be given in hospital setting (every other day or twice weekly) è availability of facilities for treatment of anaphylaxis if occurred.  Indications: Severe anemia è GA > 35 weeks & when rapid correction is needed.  Response: Each unit of blood ↑↑ Hb level by 0.5 gm/dl.  Types: 1) Packed RBCs transfusion: To avoid circulatory overload (due to hemodilution). 2) Whole blood transfusion: If packed RBCs aren't available.  Treatment of any associated condition causing anemia as ankylostoma infestation.  Treatment is assessed by clinical improvement & ↑↑ reticulocytes.  Anemia due to deficiency of folic acid or vitamin B12.  3% of cases of anemia è pregnancy.  Folic acid is reduced by reductase enzyme giving dihydrofolic acid which is further reduced by the same enzyme giving tetrahydrofolic acid (folinic acid).  Folinic acid is necessary for DNA synthesis, cell growth & cell division.  Folate requirements are ↑↑ in normal pregnancy (200-300 μg/day).  As iron deficiency anemia + the followings: ① Anticonvulsant therapy. ② Antipyretic therapy. ③ Chronic hemolysis. A. Clinical picture: As iron deficiency anemia. B. Investigations: 1) CBC: 1. Hb level: ↓↓. 2. Reticulocytic count: ↑↑. 3. Leukocytes: Hypersegmented polymorphs. 4. Blood indices: ↑↑. 2) Blood chemistry: ↓↓ plasma folate level. 3) Urinary FIGLU (form-imino-glutamic acid): ↑↑ (this differentiates folate deficiency from vitamin B12 deficiency).  Folic acid supplementation (400 μg/day) for all pregnant women. A. Mild anemia: Oral folic acid therapy (5 mg/day). B. Severe anemia near delivery: Exchange transfusion è packed RBCs followed by parenteral folic acid therapy (1 mg/day IM for 1 week).  ↑↑ incidence of: ① Megaloblastic anemia. ② IUGR. ③ NTDs. ④ Cleft lip & cleft palate.  Usually due to intrinsic factor deficiency in stomach. A. Clinical picture: As iron deficiency anemia. B. Investigations: 1) CBC: As folic acid deficiency anemia except for normal reticulocytic count. 2) Blood chemistry: ↓↓ plasma vitamin B12 level. 3) Urinary FIGLU: Normal. A. Mild anemia: Parenteral cyanocobalamin (250 μg/month IM). B. Severe anemia near delivery: Exchange transfusion è packed RBCs followed by parenteral cyanocobalamin therapy (100 μg/day IM for 1 week).