Anemia in Pregnancy: A Comprehensive Guide for Nursing Students
Table of Contents
Fig 1: Illustration of anemia in pregnancy showing iron deficiency effects and iron-rich food sources
Introduction
Anemia in pregnancy is a common hematologic condition characterized by a reduction in the concentration of hemoglobin (Hb) in the blood. It affects approximately 40% of pregnant women worldwide, making it one of the most prevalent nutritional deficiency disorders during pregnancy.
During pregnancy, significant physiologic changes occur in maternal blood composition. The plasma volume increases by about 50%, while red cell mass increases by only 20-30%. This disproportionate increase leads to hemodilution, resulting in what is sometimes called “physiologic anemia of pregnancy.”
However, true anemia in pregnancy represents a pathological state that requires proper assessment and management by healthcare providers. As nursing students, understanding the pathophysiology, diagnosis, and management of anemia in pregnancy is crucial for providing optimal care to pregnant women.
Pathophysiology
The pathophysiology of anemia in pregnancy involves multiple mechanisms depending on the specific type of anemia. However, the fundamental issue is an imbalance between the maternal red cell mass and plasma volume that results in decreased oxygen-carrying capacity.
- Plasma Volume Expansion: Increases by about 50% (1000-1500 mL) by term
- Red Cell Mass Increase: Expands by 20-30% (250-450 mL) by term
- Hemodilution: Results in a physiological drop in hemoglobin concentration
- Increased Iron Requirements: From ~1.8 mg/day to ~5-6 mg/day
- Total Iron Needs: Approximately 1000 mg additional iron needed throughout pregnancy:
- 300 mg for fetus and placenta
- 500 mg for maternal hemoglobin mass expansion
- 200 mg to compensate for normal iron losses
Memory Aid: The “50-30-20 Rule”
Remember the disproportionate changes in pregnancy:
- 50% – Plasma volume increase
- 30% – Red cell mass increase
- 20% – Resulting hemoglobin concentration decrease
This creates a “dilutional” or physiological anemia of pregnancy.
The increased demands for iron during pregnancy make women particularly susceptible to iron deficiency anemia, especially in the second and third trimesters when fetal growth accelerates. A pregnant woman’s daily iron requirements increase from ~1.8 mg/day pre-pregnancy to ~5-6 mg/day during pregnancy, which is often difficult to meet through diet alone.
Types of Anemia in Pregnancy
Several types of anemia in pregnancy may be encountered in clinical practice. Understanding the different etiologies is essential for appropriate diagnosis and management.
| Type of Anemia | Etiology | Clinical Features | Laboratory Findings |
|---|---|---|---|
| Iron Deficiency Anemia | Inadequate dietary intake, increased demands, pre-existing deficiency, or malabsorption | Fatigue, weakness, pallor, glossitis, koilonychia (spoon nails), pica | Microcytic, hypochromic RBCs, low serum ferritin, low MCV, elevated TIBC |
| Folate Deficiency Anemia | Inadequate dietary intake, increased demands, anticonvulsant therapy | Glossitis, fatigue, neural tube defects in fetus | Macrocytic anemia, normal vitamin B12 levels, low serum folate |
| Vitamin B12 Deficiency | Strict vegetarian diet, pernicious anemia, gastric bypass | Neurological symptoms, glossitis, fatigue | Macrocytic anemia, low serum B12, elevated homocysteine and methylmalonic acid |
| Anemia of Chronic Disease | Underlying chronic inflammation, infection, or malignancy | Symptoms of underlying condition plus anemia symptoms | Normocytic, normochromic anemia, normal or high ferritin, low TIBC |
| Hemoglobinopathies (Thalassemia, Sickle Cell) | Genetic disorders affecting hemoglobin structure or production | Varies by specific disorder; may include chronic hemolysis, pain crises (sickle cell) | Varies by disorder; hemoglobin electrophoresis shows abnormal patterns |
Clinical Insight
Iron deficiency anemia is by far the most common type of anemia in pregnancy, accounting for 75-95% of cases. This is due to the high iron demands of pregnancy combined with often inadequate dietary intake or pre-existing depleted iron stores.
Memory Aid: “IRON MOM”
Remember the most common types of anemia in pregnancy:
- I – Iron deficiency (most common)
- R – RBC disorders (hemoglobinopathies)
- O – Outright B12 deficiency
- N – Nutritional folate deficiency
- M – Mixed anemias
- O – Ongoing disease (anemia of chronic disease)
- M – Malabsorption syndromes
Diagnosis & Assessment
Early detection and accurate diagnosis of anemia in pregnancy are essential to minimize maternal and fetal complications.
Diagnostic Criteria
| Trimester | Hemoglobin (g/dL) | Hematocrit (%) | Severity Classification |
|---|---|---|---|
| First Trimester | < 11.0 | < 33 |
Mild: Hb 10.0-10.9 g/dL Moderate: Hb 7.0-9.9 g/dL Severe: Hb < 7.0 g/dL |
| Second Trimester | < 10.5 | < 32 | |
| Third Trimester | < 11.0 | < 33 |
Nursing Assessment
1. Health History
- Dietary habits and restrictions
- Previous anemia or hematologic disorders
- History of heavy menstrual periods
- Gastrointestinal disorders affecting absorption
- Previous pregnancies and outcomes
- Ethnic background (risk for hemoglobinopathies)
- Medication history including prenatal vitamins
2. Clinical Manifestations
- Fatigue and weakness
- Dyspnea on exertion
- Palpitations and/or tachycardia
- Pallor (conjunctival, palmar creases)
- Glossitis and angular cheilosis
- Pica (craving for non-food items)
- Koilonychia (spoon-shaped nails)
3. Laboratory Tests to Monitor
- Complete Blood Count (CBC) with indices
- Serum ferritin (most sensitive for iron deficiency)
- Transferrin saturation
- Serum B12 and folate levels (if macrocytic)
- Reticulocyte count (to assess bone marrow response)
- Peripheral blood smear
- Hemoglobin electrophoresis (if hemoglobinopathy suspected)
Clinical Pearl
Inflammation can falsely elevate serum ferritin levels, masking iron deficiency. In pregnant women with inflammatory conditions, a ferritin level < 30 ng/mL still suggests iron deficiency. Consider measuring C-reactive protein (CRP) alongside ferritin to identify inflammation.
Memory Aid: “ANEMIA” Assessment
Use this mnemonic for a comprehensive assessment:
- A – Appearance (pallor, glossitis)
- N – Nutritional status and intake
- E – Energy levels (fatigue, activity tolerance)
- M – Medical history and medications
- I – Iron studies and indices (lab values)
- A – Additional symptoms (pica, koilonychia)
Complications
Anemia in pregnancy can lead to serious complications for both the mother and fetus if left untreated, especially when severe.
- Cardiovascular Strain: Tachycardia, palpitations, increased cardiac output
- Reduced Exercise Tolerance: Fatigue, dyspnea, decreased quality of life
- Preterm Labor: Increased risk of delivering before 37 weeks
- Placental Abruption: Higher risk, especially with severe anemia
- Postpartum Hemorrhage: Increased risk and reduced ability to tolerate blood loss
- Postpartum Depression: Higher incidence associated with anemia
- Increased Infection Risk: Impaired immune function
- Intrauterine Growth Restriction (IUGR): Reduced oxygen delivery to the fetus
- Low Birth Weight: Less than 2500g at birth
- Preterm Birth: Before 37 completed weeks of gestation
- Perinatal Mortality: Increased risk, especially with severe anemia
- Developmental Delays: Possible long-term neurological effects
- Neonatal Anemia: Especially with severe maternal anemia
Critical Alert
Severe anemia (Hb < 7 g/dL) during pregnancy is associated with significant adverse outcomes. Research shows that maternal mortality risk increases by 2.5 times with severe anemia. Early identification and aggressive treatment are essential.
Nursing Management
Effective nursing management of anemia in pregnancy involves assessment, planning, implementation, and evaluation.
Nursing Diagnoses
| Nursing Diagnosis | Related Factors |
|---|---|
| Activity Intolerance | Decreased oxygen-carrying capacity, fatigue, weakness |
| Imbalanced Nutrition: Less than Body Requirements | Inadequate iron/folate intake, poor absorption, increased requirements |
| Risk for Impaired Fetal Development | Decreased maternal oxygen-carrying capacity, nutritional deficiencies |
| Ineffective Tissue Perfusion | Reduced hemoglobin levels, impaired oxygen transport |
| Deficient Knowledge | Unfamiliarity with nutritional requirements, iron supplementation |
Nursing Interventions
- Perform regular assessment of vital signs, especially heart rate and respiratory rate
- Monitor for signs and symptoms of worsening anemia
- Track laboratory values (Hb, Hct, MCV, MCH, ferritin)
- Assess fetal well-being through appropriate monitoring
- Monitor response to treatment with follow-up laboratory tests
1. Oral Iron Supplementation
- Administer oral iron supplements as prescribed (typically 60-120 mg elemental iron daily)
- Educate about proper administration:
- Take on an empty stomach or with vitamin C-rich foods to enhance absorption
- Avoid taking with calcium, antacids, tea, coffee, or dairy products
- Space doses appropriately if multiple daily doses are prescribed
- Monitor for side effects: constipation, nausea, epigastric discomfort, black stools
- Implement strategies to manage side effects
2. Intravenous Iron Therapy
- Prepare and administer IV iron as prescribed for severe anemia or oral iron intolerance
- Monitor for potential adverse reactions during administration (allergic reactions, hypotension)
- Have emergency equipment readily available during administration
- Assess injection site for extravasation when using IV iron
- Document administration and patient response
3. Blood Transfusion (Severe Cases)
- Prepare patient for transfusion if prescribed for severe anemia
- Verify blood products using institutional protocol
- Monitor vital signs before, during, and after transfusion
- Observe for transfusion reactions
- Document transfusion, including amount and patient response
4. Folate and Vitamin B12 Supplementation
- Administer folic acid supplements as prescribed (typically 0.4-1 mg daily)
- Ensure adequate vitamin B12 supplementation for deficient patients
- Educate about dietary sources of folate and B12
- Provide education about anemia, its causes, and potential complications
- Teach energy conservation techniques for managing fatigue
- Counsel on optimal nutrition and iron-rich foods
- Provide guidance on supplement administration and side effect management
- Emphasize the importance of medication adherence and follow-up
- Support emotional well-being and address concerns
Memory Aid: “IRON Care”
Key nursing interventions for anemia in pregnancy:
- I – Intake assessment (dietary evaluation)
- R – Recommend supplements as prescribed
- O – Observe for side effects and complications
- N – Nutrition education (iron-rich foods)
- C – Conservation of energy techniques
- A – Assess treatment effectiveness
- R – Regular monitoring of lab values
- E – Education about medication administration
Prevention Strategies
Prevention of anemia in pregnancy focuses on adequate nutrition and supplementation before and during pregnancy.
- Screen for anemia and treat existing deficiencies before conception
- Begin folic acid supplementation (0.4-0.8 mg daily) at least one month before conception
- Optimize iron stores through nutrition and/or supplementation
- Address any chronic conditions that may contribute to anemia
- Provide education on iron-rich foods and absorption enhancers
1. Universal Supplementation
- Current CDC and ACOG recommendation: 30 mg elemental iron daily for all pregnant women
- Continue folic acid supplementation (0.4-0.8 mg daily) throughout pregnancy
- Consider higher doses for women at increased risk of deficiency
2. Nutritional Counseling
- Promote intake of iron-rich foods:
- Animal sources: lean red meat, poultry, fish
- Plant sources: lentils, beans, spinach, fortified cereals
- Encourage vitamin C-rich foods with meals to enhance iron absorption
- Advise on foods to avoid during iron supplementation (tea, coffee, dairy)
3. Regular Screening
- CBC at first prenatal visit
- Repeat CBC at 24-28 weeks gestation
- Additional testing based on risk factors or symptoms
Latest Guidelines Update
As of 2024, the Centers for Disease Control and Prevention (CDC) and American College of Obstetricians and Gynecologists (ACOG) recommend universal supplementation with low-dose iron (30 mg/day) for all pregnant persons, except in specific conditions such as hemochromatosis.
Patient Education
Effective patient education is essential for managing anemia in pregnancy and promoting positive outcomes.
1. Understanding Anemia
- Explain what anemia is and why it occurs during pregnancy
- Discuss potential complications if left untreated
- Emphasize the importance of treatment adherence
2. Iron Supplementation
- How to take iron supplements correctly:
- Best taken on an empty stomach (1 hour before or 2 hours after meals)
- If GI upset occurs, can be taken with food (though absorption may be reduced)
- Take with vitamin C (orange juice, etc.) to enhance absorption
- Common side effects and management:
- Constipation: increase fluid intake, dietary fiber, gentle exercise
- Nausea: take with small amounts of food, try different formulations
- Black stools: normal and expected
- Liquid iron formulations may cause temporary tooth staining; use a straw
3. Dietary Recommendations
- Iron-rich foods:
- Heme iron (better absorbed): lean red meat, liver, poultry (dark meat), fish
- Non-heme iron: legumes, tofu, spinach, kale, fortified cereals, dried fruits
- Vitamin C-rich foods to enhance iron absorption:
- Citrus fruits, strawberries, bell peppers, tomatoes, broccoli
- Foods to limit with iron supplements:
- Calcium-rich foods (milk, cheese, yogurt)
- Tannin-containing beverages (tea, coffee)
- High-fiber foods (can interfere with absorption)
4. Signs to Report
- Worsening fatigue or weakness
- Dizziness or fainting
- Shortness of breath at rest
- Chest pain or palpitations
- Severe headache
- Changes in fetal movement
5. Follow-up Importance
- Importance of keeping prenatal appointments
- Need for follow-up laboratory tests to monitor response to treatment
- Continuation of supplements as directed, even after feeling better
Teaching Tip
Use visual aids and food models to help patients identify iron-rich foods. Consider providing a wallet-sized card listing iron-rich foods and those that enhance or inhibit absorption for easy reference during grocery shopping.
Best Practices & Updates
3 Key Updates in Anemia in Pregnancy Management
1. Intravenous Iron: Earlier Consideration
Recent studies show that IV iron therapy should be considered earlier in pregnancy for women with moderate to severe anemia or those who do not respond to oral iron. A 2025 study found that early intervention with IV iron is safe and effective, with improved maternal and neonatal outcomes compared to delayed treatment.
IV iron preparations like iron sucrose and ferric carboxymaltose have demonstrated safety profiles in pregnancy with faster hemoglobin response than oral iron.
2. Improved Diagnostic Approach
Current best practice includes using serum ferritin as an initial screening test for iron deficiency, even before anemia develops. Iron deficiency without anemia can still impact maternal and fetal outcomes.
The latest guidelines recommend ferritin testing in addition to CBC for all pregnant women at their first prenatal visit, with a threshold of <30 ng/mL indicating iron deficiency requiring treatment, even with normal hemoglobin levels.
3. Enhanced Supplementation Strategies
Research now supports alternative iron supplementation schedules to improve adherence and reduce side effects. Intermittent iron supplementation (2-3 times weekly rather than daily) has shown similar effectiveness with fewer gastrointestinal side effects in mild to moderate anemia.
Additionally, newer iron formulations with improved tolerability, such as iron bisglycinate and sucrosomial iron, are emerging as options for women who experience significant gastrointestinal side effects with traditional iron salts.
Memory Aids
“RED FLAG” Signs of Severe Anemia
Remember these concerning symptoms that require immediate attention:
- R – Respiration difficulties (shortness of breath at rest)
- E – Extreme fatigue (unable to perform daily activities)
- D – Dizziness or syncope
- F – Fast heart rate (>100 bpm at rest)
- L – Low hemoglobin (<7 g/dL)
- A – Altered mental status
- G – Growth restriction (fetal)
“IRON BOOST” Diet Plan
Help patients remember dietary recommendations:
- I – Include meat, especially red meat (heme iron)
- R – Red and organ meats (liver, kidney)
- O – Oysters and other shellfish
- N – Nuts and seeds (pumpkin seeds, cashews)
- B – Beans and legumes
- O – Oatmeal and fortified cereals
- O – Orange juice with meals (vitamin C)
- S – Spinach and dark leafy greens
- T – Tofu and soy products
Hemoglobin Thresholds: “11-10.5-11”
Remember the trimester-specific hemoglobin thresholds for diagnosing anemia:
- First trimester: <11 g/dL
- Second trimester: <10.5 g/dL
- Third trimester: <11 g/dL
References
- American College of Obstetricians and Gynecologists. (2023). Anemia in Pregnancy: ACOG Practice Bulletin No. 233. Obstetrics and Gynecology.
- Centers for Disease Control and Prevention. (2024). Recommendations to prevent and control iron deficiency in the United States.
- World Health Organization. (2025). Daily iron and folic acid supplementation during pregnancy. WHO Guidelines.
- Society for Maternal-Fetal Medicine. (2025). Large Study Finds IV Iron Treatment During Pregnancy Safe and Effective for Anemia.
- Cunningham, F. G., Leveno, K. J., Bloom, S. L., Dashe, J. S., Hoffman, B. L., Casey, B. M., & Spong, C. Y. (2023). Williams Obstetrics (26th ed.).
- Pavord, S., Myers, B., Robinson, S., Allard, S., Strong, J., & Oppenheimer, C. (2022). UK guidelines on the management of iron deficiency in pregnancy. British Journal of Haematology.
- Auerbach, M., Abernathy, J., Juul, S., Short, V., & Derman, R. (2023). Prevalence of iron deficiency in first trimester, nonanemic pregnant women. The Journal of Maternal-Fetal & Neonatal Medicine.