HOW ANEMIA AFFECTS PREGNANT WOMEN AND THEIR BABIES

Anemia in pregnancy is a significant global health challenge, associated with adverse outcomes for both the mother and the developing fetus. Its timely identification and effective management are critical components of comprehensive antenatal care.

Defining Anemia in Pregnancy: The WHO Standard

The World Health Organization (WHO) employs specific haemoglobin (Hb) thresholds to define anemia in pregnant women, recognizing the physiological changes that occur throughout gestation, particularly the expansion of plasma volume relative to red blood cell mass (hemodilution). These thresholds are:

• First Trimester (Weeks 0-12): Haemoglobin less than 11.0 g/dL
• Second Trimester (Weeks 13-28): Haemoglobin less than 10.5 g/dL
• Third Trimester (Weeks 29-40): Haemoglobin less than 11.0 g/dL

A haemoglobin level below 7.0 g/dL at any point during pregnancy is typically classified as severe anemia, requiring more urgent attention and often different management strategies compared to mild or moderate anemia. These definitions serve as crucial benchmarks for screening, diagnosis, and monitoring pregnant women globally.

Types of Anemia in Pregnancy

Anemia during pregnancy can arise from numerous causes, reflecting various underlying deficiencies, genetic conditions, or chronic illnesses. While the most common type relates to inadequate iron intake, it is important to recognize other potential etiologies. The main types encountered include:

• Iron Deficiency Anemia (IDA): This is by far the most prevalent type of anemia in pregnancy, accounting for the vast majority of cases. Pregnancy significantly increases the mother’s iron requirements due to the demands of the growing fetus and placenta, the expansion of maternal red cell mass, and blood loss during delivery. Inadequate dietary iron intake, poor absorption, or short intervals between pregnancies can exacerbate this risk.
• Megaloblastic Anemia:
  • Folate Deficiency: Folate (folic acid) requirements also increase substantially in pregnancy due to rapid cell division and growth. Deficiency can lead to the production of abnormally large red blood cells (megaloblasts). Folate deficiency is a significant concern due to its association with neural tube defects in the fetus, in addition to causing anemia.
  • Vitamin B12 (Cobalamin) Deficiency: Although less common than folate deficiency in pregnancy, B12 is also essential for DNA synthesis and red blood cell formation. Deficiency can occur in women with inadequate dietary intake (especially vegetarians/vegans without supplementation), malabsorption disorders, or pernicious anemia.
• Anemia of Chronic Disease or Inflammation: This type of anemia can occur in pregnant women with underlying chronic conditions such as inflammatory bowel disease, renal disease, or chronic infections. Inflammation can impair iron utilization by the body, even if iron stores are adequate, and suppress erythropoiesis (red blood cell production).
• Hemoglobinopathies: These are inherited genetic disorders affecting the structure or production of haemoglobin.
  • Thalassemias: Conditions like Beta-thalassemia or Alpha-thalassemia can range from mild (trait) to severe. Pregnant women with thalassemia trait may present with a mild, microcytic (small red blood cell) anemia that does not respond to iron therapy (as iron stores are normal or elevated). More severe forms require specialized management.
  • Sickle Cell Disease/Trait: Sickle cell disorders affect the shape of red blood cells, leading to chronic anemia, pain crises, and organ damage. Pregnancy in women with sickle cell disease is high-risk and requires close monitoring and specialized care.
• Other Less Common Types: These can include aplastic anemia (failure of bone marrow to produce blood cells), hemolytic anemias (premature destruction of red blood cells), or anemias related to other nutritional deficiencies or underlying medical conditions.

Clinical Presentation and Manifestations

The signs and symptoms of anemia in pregnancy can vary widely depending on the severity and the underlying cause. Mild to moderate anemia may be asymptomatic, often detected only through routine antenatal blood tests. More severe anemia can manifest with a range of symptoms and signs, affecting both the mother and potentially the fetus.

Common Maternal Symptoms:

• Fatigue and Weakness: This is often the most common and earliest symptom, although fatigue is also a non-specific symptom of normal pregnancy.
• Pallor: Paleness of the skin, conjunctivae (inner eyelids), nail beds, and mucous membranes.
• Shortness of Breath (Dyspnea): Especially on exertion.
• Dizziness or Lightheadedness.
• Headaches.
• ** palpitations or awareness of heart beat.**
• Cold Hands and Feet.

Less Common or More Specific Symptoms/Signs (can vary by type):

• Pica: Cravings for non-food substances like ice (pagophagia), clay, or dirt (more common in severe iron deficiency).
• Restless Legs Syndrome.
• Sore Tongue (Glossitis) or Mouth Ulcers: Can be associated with iron, folate, or B12 deficiency.
• Brittle Nails or Koilonychia (Spoon-shaped nails): Severe iron deficiency.
• Jaundice: May occur in hemolytic anemias.
• Neurological symptoms (e.g., tingling, numbness, gait disturbance): Specifically with severe B12 deficiency (though rare in pregnancy).

Potential Maternal Complications of Severe Anemia:

• Increased risk of infection.
• Increased risk of postpartum hemorrhage.
• Increased risk of requiring blood transfusion.
• Increased maternal mortality (in very severe cases).
• Reduced tolerance for blood loss during delivery.
• Severe fatigue impacting care for the newborn.

Potential Fetal/Neonatal Implications (especially with severe or specific types like B12/folate deficiency):

• Increased risk of preterm birth.
• Increased risk of low birth weight.
• Potential links to impaired cognitive or physical development (especially with severe iron deficiency).
• Increased risk of neural tube defects (with folate deficiency).
• Increased risk of fetal distress.

Main Investigations for Anemia in Pregnancy

Diagnosing anemia and identifying its cause during pregnancy typically involves a combination of clinical assessment and laboratory tests. Routine screening for anemia is recommended early in pregnancy and often again in the second or third trimester.

Key Investigations Include:

• Complete Blood Count (CBC): This is the initial and most fundamental test. It measures:
  • Haemoglobin (Hb) level: To confirm anemia based on WHO criteria.
  • Hematocrit (Hct): The percentage of blood volume occupied by red blood cells.
  • Mean Corpuscular Volume (MCV): Average size of red blood cells (low in iron deficiency/thalassemia, high in megaloblastic anemia).
  • Mean Corpuscular Hemoglobin (MCH) and Mean Corpuscular Hemoglobin Concentration (MCHC): Relate to the amount of haemoglobin in red cells (typically low in iron deficiency/thalassemia).
  • Red Cell Distribution Width (RDW): Measures variation in red cell size (often elevated in iron deficiency).
  • Platelet Count and White Blood Cell Count: To assess other blood components.
• Peripheral Blood Smear: Microscopic examination of a blood sample to look at the shape, size, and appearance of red blood cells, white blood cells, and platelets. It can help differentiate between various types of anemia (e.g., microcytic, macrocytic, presence of abnormal cells).
• Iron Studies: These tests are crucial for diagnosing iron deficiency anemia:
  • Serum Ferritin: The most sensitive indicator of the body’s iron stores. Low levels (<30 µg/L, though thresholds can vary slightly) strongly suggest iron deficiency, even before anemia develops. Ferritin can be falsely normal or elevated in the presence of inflammation or infection, which needs to be considered.
  • Serum Iron: Measures the amount of iron in the blood, but fluctuates.
  • Total Iron-Binding Capacity (TIBC): Measures the capacity of transferrin (the protein that transports iron) to bind iron (typically high in iron deficiency).
  • Transferrin Saturation: Calculated from serum iron and TIBC (typically low in iron deficiency).
• Serum Folate and Vitamin B12 Levels: Measured when megaloblastic anemia is suspected (high MCV on CBC or relevant clinical signs). It’s important to measure both, as deficiency of one can mask the deficiency of the other.
• Hemoglobin Electrophoresis and/or Genetic Testing: Performed if a hemoglobinopathy (like thalassemia or sickle cell trait/disease) is suspected, especially if MCV is low and iron stores are normal, or if there is a relevant family history or ethnic background.
• Tests for Underlying Conditions: Depending on the clinical picture, investigations for chronic disease, kidney function, or signs of hemolysis may be warranted.

Treatment for the Most Common Causes of Anemia in Pregnancy

The treatment of anemia in pregnancy is tailored to the specific cause and severity. Given that Iron Deficiency Anemia (IDA) is the most common, its management is detailed below, along with brief notes on managing other common nutritional deficiencies.

A. Management of Iron Deficiency Anemia (IDA):

The primary goal is to replenish iron stores and normalize haemoglobin levels, improving maternal well-being and optimizing fetal development.

1. Dietary Advice:
   • Educate on iron-rich foods:
     • Heme iron (easily absorbed): Red meat, poultry, fish.
     • Non-heme iron: Beans, lentils, fortified cereals, spinach, nuts, seeds.
   • Advise on enhancers: Vitamin C (e.g., orange juice) enhances non-heme iron absorption when consumed together.
   • Advise on inhibitors: Avoid consuming large amounts of tea, coffee, calcium-rich foods (dairy), or calcium supplements concurrently with iron-rich meals or iron supplements, as they can reduce absorption.
   • Note: Dietary changes alone are usually insufficient to treat established anemia in pregnancy but are important for prevention and maintenance.
2. Oral Iron Supplementation:
   • This is the cornerstone of IDA treatment in pregnancy for mild to moderate cases.
   • Choice of Preparation: Ferrous salts (sulfate, fumarate, gluconate) are commonly used and generally well-absorbed. Different preparations contain varying amounts of elemental iron. Ferrous sulfate is often the first choice due to cost and availability.
   • Dosage: Typically, the equivalent of 100-200 mg of elemental iron per day is prescribed, usually divided into 1-2 doses. Starting with a lower dose might help improve tolerance.
   • Administration: Best absorbed on an empty stomach (one hour before or two hours after meals), potentially with Vitamin C. However, if gastrointestinal side effects occur, taking the supplement with a small amount of food is acceptable, though absorption may be slightly reduced.
   • Side Effects: Common side effects include nausea, constipation, abdominal pain, and blackening of stools. Management strategies include taking with food, starting with a lower dose and gradually increasing, switching to a different iron salt, or prescribing stool softeners for constipation.
   • Monitoring: Haemoglobin levels should be rechecked after 2-4 weeks of consistent therapy to assess response. Haemoglobin should rise by at least 1 g/dL over 2-4 weeks if treatment is effective and compliance is good.
   • Duration: Treatment should continue for several months after the haemoglobin level has normalized (ideally until postpartum, and even beyond) to fully replenish iron stores (reflected by ferritin levels).
3. Parenteral Iron Therapy:
   • Indicated in specific situations:
     • Severe anemia requiring rapid correction (e.g., late in pregnancy).
     • Intolerance to oral iron supplements (severe side effects despite trying different preparations/strategies).
     • Malabsorption syndromes.
     • Proven non-compliance with oral therapy.
   • Preparation: Various intravenous iron preparations are available (e.g., iron sucrose, ferric carboxymaltose, iron isomaltoside). They are administered via infusion.
   • Benefits: Can deliver a large dose of iron quickly and is not subject to absorption variability or gastrointestinal side effects.
   • Risks: Risk of infusion reactions (usually mild, but rarely severe allergic reactions), phlebitis at the infusion site. Requires administration in a clinical setting with trained personnel and observation.

B. Management of Folate Deficiency:

• Treatment: Oral folic acid supplementation at a therapeutic dose, typically 5 mg once daily.
• Duration: Treatment continues until haemoglobin normalizes and often throughout the remainder of the pregnancy and postpartum to build stores and prevent recurrence.
• Prevention: Routine periconceptional and antenatal folic acid supplementation (usually 400 µg per day, but up to 5 mg for high-risk individuals, e.g., previous child with neural tube defect) is standard care and has significantly reduced the incidence of folate deficiency anemia and neural tube defects.

C. Management of Vitamin B12 Deficiency:

• Treatment: Parenteral (intramuscular) vitamin B12 injections are often preferred, especially if malabsorption is suspected. Dosage and frequency depend on severity, but loading doses followed by maintenance injections are common.
• Oral B12 can be effective for pernicious anemia due to passive absorption if very high doses are used, but injections are generally more reliable.
• Investigation: Crucial to investigate the underlying cause of B12 deficiency (e.g., pernicious anemia, malabsorption) to ensure appropriate long-term management.

D. Management of Other Anemias (e.g., Hemoglobinopathies, Anemia of Chronic Disease):

• These require management specific to the underlying condition.
• Often involve specialist care (e.g., hematologists).
• Treatment may include red blood cell transfusions for severe cases (e.g., severe thalassemia, sickle cell crisis), management of the underlying chronic disease, or other specific therapies. Iron supplementation is often contraindicated in iron-loaded conditions like some thalassemias.

Conclusion

Anemia in pregnancy, defined by the WHO haemoglobin thresholds, is a multifaceted issue requiring systematic screening and a targeted approach to diagnosis and treatment. Iron deficiency remains the predominant cause, effectively managed in most cases with oral iron supplementation, appropriate dietary advice, and monitoring. Other forms, such as megaloblastic anemia, also have specific effective treatments. Prompt recognition, investigation to determine the specific type, and appropriate management based on established guidelines are essential to mitigate the risks associated with anemia, safeguarding the health and well-being of both the mother and her child. Regular antenatal check-ups including anemia screening are vital for ensuring healthy pregnancy outcomes.