Anemia in Pregnancy

Definition

Anemia is the commonest hematological disorder that may occur in pregnancy.

Hb ≤11g/dL [WHO]

Anemic Hb in pregnancy

1st trimester: <11 g/dL

2nd trimester: <10.5 g/dL

3rd trimester: <10 g/dL

Severity

Mild: 9.0 - 11.0

Moderate: 7.0 - 9.0

Severe: <7.0

Prevalence

Estimation >40% of pregnancies are complicated by anemia [WHO]

Malaysia - 12% in 1st trimester, 32% in 2nd trimester, 43% in 3rd trimester

Etiology

  1. Physiological

  2. Iron deficiency

  3. Folic acid deficiency

  4. Vit B12 deficiency

  5. APH

  6. Chronic hookworm infestation

  7. Thalassemia

  8. Autoimmune hemolytic disease (AIHA, SLE)

  9. Sickle cell disease

  10. Hypothyroidism

  11. Chronic renal disease

Pathophysiology

  • Higher increase of plasma volume compared to RBC volume

  • RBC becomes diluted -> hemodilution

  • Increased demand of iron during pregnancy

  • Iron deficiency -> ↓ serum iron, ↑ TIBC -> negative iron balance

Signs & Symptoms

Anemic symptoms:

  1. Palpitation

  2. SOB

  3. Dizziness

  4. Presyncopal attack

  5. Lethargy

Complications

Maternal

  1. PPH

  2. Cardiac failure during labour

  3. Subinvolution

  4. Pulmonary embolism

Fetal

  1. IUGR

  2. Neural tube defect (folate deficiency)

  3. Intrauterine death

History

  1. Dietary intake

  2. Supplement - folic acid, vit B12

  3. Family h/o thalassemia

  4. APH

  5. h/o anemia - pre-pregnant & prev pregnancy

  6. h/o blood transfusion

Physical Examination

  1. Palm & nail bed - pale

  2. Conjunctival pallor

  3. Tongue - pale, glossitis (chronic IDA)

Screening

  • Booking

  • 24-28 weeks

  • 36 weeks

Investigations

  1. FBC - to identify the severity, type of anemia

  2. Mentzer index - MCV/RBC (<13 likely thalassemia, >13 likely IDA)

  3. FBP & peripheral blood smear - TRO thalassemia or sickle cell

  4. UFEME

  5. Iron studies - TIBC, serum iron/ferritin

  6. Serum folate/B12 (if required)

  7. Stool ova cyst - if suspected hookworm infestation

Management

Dietary advice

  • Iron rich food: spinach, saltwater fish, meats, seafood

  • Iron absorption enhancers: vit C

  • Iron absorption inhibitors: coffee, tea, polyphenols, eggs, milk

Iron preparations

  • Prophylaxis: 100mg/day elemental iron + 5mg folic acid

  • Treatment: 180mg/day elemental iron + 5mg folic acid

Preparation Elemental iron (mg/tablet)
Obimin 30 ferrous sulphate
Ferrous fumarate 60 ferrous fumarate
Iberet 105mg ferrous sulphate
Zincofer 115mg ferrous sulphate
Maltofer 100mg ferric hydroxide polymaltose

Parenteral Iron

Indications:

  • insufficient/no response to oral iron

  • severe anemia

  • insufficient absorption of oral iron

  • intolerance of oral iron

  • poor compliance

Parenteral iron Route of administration Elemental iron (mg/mL)
Iron dextran (Cosmofer) IM or IV 50
Iron sucrose (Venofer) IV 20