History Taking for Anemia at 36 Weeks Gestation
For a pregnant woman at 36 weeks presenting with low blood levels, obtain a focused history targeting iron deficiency causes, risk factors for other anemias, and symptoms that could affect maternal-fetal outcomes.
Essential Historical Components
Dietary and Nutritional History
- Iron intake assessment: Quantify consumption of red meat, eggs, and iron-rich foods. Women consuming eggs less than twice weekly have 1.7 times higher odds of anemia 1, 2
- Tea consumption: Document if drinking more than 3 cups daily, which triples anemia risk (aPOR 3.2) 2
- Vegetarian diet: Iron requirements nearly double in purely vegetarian diets due to poor absorption of non-heme iron 1
- Pica behavior: Specifically ask about clay or dirt consumption during pregnancy (aPOR 3.7 for anemia) 2
- Medications affecting absorption: Document antacid use or gastrointestinal medications that decrease iron absorption 1
Obstetric and Gynecologic History
- Timing of prenatal care initiation: Late registration (after first trimester) increases anemia odds 1.7-1.9 times 3, 4
- Interpregnancy interval: Short intervals between pregnancies increase risk 1
- Parity: Women with parity ≥2 have higher iron deficiency rates 1
- Current pregnancy complications: Ask about bleeding, multiple gestation (specifically monochorionic twins with 3-5% risk of twin anemia-polycythemia sequence) 5
Blood Loss History
- Gastrointestinal bleeding: Any history of ulcers, hemorrhoids, or blood in stool
- Antepartum bleeding: Document any vaginal bleeding during current pregnancy
- Previous postpartum hemorrhage: Relevant for assessing iron stores 1
Symptoms and Functional Impact
- Anemia symptoms: Fatigue severity, dyspnea, dizziness, palpitations
- Infection history: Current or recent infections (anemia increases infection susceptibility) 6
- Cardiac symptoms: Chest pain, severe dyspnea (anemia causes cardiac complications) 6
Risk Factors for Non-Iron Deficiency Anemia
- Ethnicity: Non-Hispanic Black and Mexican American women have higher prevalence 1
- Family history: Hemoglobinopathies (thalassemia, sickle cell disease) 5
- Infection exposure:
- Chronic diseases: Kidney disease, autoimmune conditions, chronic infections 5
Current Supplementation
- Iron supplementation: Dose, duration, compliance, and tolerance (nausea, constipation, diarrhea are common) 1
- Prenatal vitamins: Type and iron content (typical prenatal contains 30-48 mg elemental iron) 1
Socioeconomic Factors
- Educational level: Lower education correlates with higher anemia risk 4
- Household wealth: Low socioeconomic status increases risk 3
Critical Red Flags to Identify
Immediate concern indicators:
- Hemoglobin <7 g/dL or cardiorespiratory symptoms (may require transfusion) 7
- Hydrops fetalis risk if severe fetal anemia suspected 5
- Signs of preterm labor (anemia increases risk) 6
- Symptoms of postpartum hemorrhage risk assessment 6
Common Pitfalls to Avoid
- Don't assume all anemia is iron deficiency: At 36 weeks, only 19.9% of anemia cases are confirmed iron deficiency; hemoglobinopathies account for 28.1% 4
- Don't overlook physiologic hemodilution: Normal pregnancy causes plasma volume expansion, making hemoglobin interpretation complex at this gestational age 1
- Don't forget alloimmunization: While Rh(D) is less common now, anti-Kell, anti-c, anti-E, anti-Duffy, and anti-Kidd antibodies cause severe fetal anemia 5
The history should directly inform whether this represents simple iron deficiency amenable to oral supplementation (60-120 mg elemental iron daily) 7 versus a more complex etiology requiring specialized testing and potentially delivery planning at 37-38 weeks if fetal anemia is suspected 5.