What is the cause and recommended management for a pregnant woman at 11 weeks gestation with symptoms of fatigue and lightheadedness and a hemoglobin (Hb) level of 11.5 g/dL, indicating mild anemia?

Physiologic Anemia of Pregnancy with Symptomatic Mild Anemia

This patient has physiologic anemia of pregnancy (hemoglobin 11.5 g/dL at 11 weeks) causing symptomatic fatigue and lightheadedness, and should be started on oral iron supplementation at 60-120 mg elemental iron daily to correct the anemia and replenish iron stores. 1

Understanding the Cause

Physiologic Hemodilution

• All pregnant women develop a degree of physiologic anemia due to blood volume expansion and hemodilution 2
• At 11 weeks gestation, hemoglobin <11 g/dL is considered anemic (normal cutoff is >11 g/dL in the first trimester) 1
• This patient's hemoglobin of 11.5 g/dL is borderline but her symptoms of fatigue and lightheadedness indicate she is symptomatic from relative anemia 2

Iron Deficiency as the Likely Underlying Cause

• While physiologic hemodilution occurs in all pregnancies, symptomatic anemia at this level typically reflects underlying iron deficiency 1
• Check serum ferritin to confirm iron deficiency, with ferritin <45 ng/mL confirming iron deficiency anemia 1
• A complete blood count with MCV and RDW should be obtained to characterize the anemia 1

Treatment Protocol

Oral Iron Supplementation

• Prescribe 60-120 mg of elemental iron daily as first-line treatment 1
• Treatment should continue until hemoglobin normalizes for gestational age, then reduce to a maintenance dose of 30 mg/day 1
• Counsel the patient that iron may cause gastrointestinal discomfort, nausea, constipation, or diarrhea 3
• Do not take iron within 2 hours of tetracycline antibiotics, as iron interferes with tetracycline absorption 3

Dietary Counseling

• Advise consuming iron-rich foods (red meat, poultry, fish, legumes, fortified cereals) 1
• Recommend foods that enhance iron absorption, particularly vitamin C-containing foods (citrus fruits, tomatoes, peppers) taken with iron supplements 1

Monitoring Response

• Reassess hemoglobin after 4 weeks of treatment, expecting at least a 1 g/dL increase in hemoglobin or 3% increase in hematocrit 1
• If no response after 4 weeks despite compliance and absence of acute illness, further evaluation with MCV, RDW, and serum ferritin is necessary 1

Activity and Exercise Recommendations

Physical Activity Should Continue

• Women with hemoglobin levels >10 g/dL (100 g/L) who are asymptomatic should maintain moderate-vigorous physical activity 2
• If symptomatic (as this patient is), she may consider reducing the intensity of prenatal exercise but should remain physically active 2
• There is no evidence that anemia at this level is a contraindication to exercise in pregnancy 2
• Light physical activity and activities of daily living should be maintained at minimum 2

When to Escalate Care

Referral Indications

• Refer to a physician familiar with anemia in pregnancy if hemoglobin drops to <9.0 g/dL or hematocrit <27.0% 1
• If no response to iron therapy after 4 weeks in women of African, Mediterranean, or Southeast Asian ancestry, consider thalassemia minor or sickle cell trait 1

Transfusion is NOT Indicated

• Transfusion is not indicated at hemoglobin 11.5 g/dL in a stable pregnant patient 1
• Blood transfusions should be reserved for patients with or at risk of cardiovascular instability due to the degree of their anemia 2

Critical Pitfalls to Avoid

• Do not dismiss symptoms of fatigue and lightheadedness as "normal pregnancy symptoms" without addressing the anemia 2
• Do not restrict physical activity unnecessarily, as complete inactivity could result in increased risk of adverse pregnancy outcomes 2
• Do not delay iron supplementation while waiting for ferritin results if clinical suspicion for iron deficiency is high 1
• Ensure proper child-resistant closures on iron supplements, as required by the U.S. Consumer Product Safety Commission 3