Screening and Supplementation for Iron Deficiency and Iron Deficiency Anemia During Pregnancy

A 22-year-old patient (gravida 2, para 1) is beginning prenatal care. She had a positive home pregnancy test result 1 week ago. Per the patient’s last menstrual period, the pregnancy is at 12 weeks and 3 days of gestation. The patient has no known chronic medical conditions and is inquiring about recommended first-trimester screening tests, including iron deficiency anemia.

1. Which of the following risk factors would increase suspicion for asymptomatic first-trimester iron deficiency anemia in this patient?

• A. Eating a diet low in iron-rich foods.
• B. Using tobacco.
• C. Being of Black race or Mexican American ethnicity.
• D. Living at a high altitude.
• E. Having a short interval between pregnancies.

2. Which one of the following statements best describes the US Preventive Services Task Force (USPSTF) recommendation on screening for iron deficiency or iron deficiency anemia?

• A. There is convincing evidence that early detection results in improved maternal and fetal outcomes.
• B. Patients should not be screened because sufficient evidence exists to suggest screening could result in maternal or fetal harm.
• C. Only patients with symptoms of iron deficiency should be screened, which allows for earlier treatment to reduce the risk of poor maternal or fetal outcomes.
• D. Physicians should use clinical judgment when deciding to screen patients.

3. According to the USPSTF recommendation statement on screening for iron deficiency or iron deficiency anemia, which one of the following statements about iron supplementation in pregnancy is correct?

• A. It has been shown to increase maternal hematologic indices (eg, hemoglobin).
• B. It has been shown to improve maternal and neonatal morbidity and mortality.
• C. It has been shown to increase neonatal hematologic indices.
• D. It is recommended in pregnant patients with symptomatic anemia.

1. The correct answers are A, C, and E. Diets low in iron-rich foods (such as a vegan diet) and short intervals between pregnancies are risk factors for iron deficiency anemia in pregnancy.¹ In addition, data suggest that there is an increased prevalence of iron deficiency anemia in Black and Mexican American pregnant women. Tobacco use (carbon monoxide exposure) and living at a high altitude (lower partial pressure of oxygen) are not commonly cited risk factors, but they may cause chronic hypoxic conditions that can result in increased erythropoiesis and hemoglobin production and mask underlying iron deficiency or iron deficiency anemia.²
2. The correct answer is D. The USPSTF reviewed the evidence on screening and supplementation for iron deficiency and iron deficiency anemia during pregnancy to determine whether these services improved the health of pregnant women and their infants. However, not enough evidence was found regarding the effectiveness of screening.³ In the absence of evidence, clinicians should use their judgment and listen to any patient concerns when deciding whether to screen.
3. The correct answer is A. Although iron supplementation has been shown to increase maternal hematologic indices, there is insufficient evidence to assess whether iron supplementation during pregnancy improves patient health outcomes, such as maternal and neonatal morbidity and mortality, according to systematic review.³ Potential harms of iron supplementation include gastrointestinal symptoms such as nausea, constipation, abdominal pain, vomiting, and iron overload. In the absence of evidence, clinicians should use their judgment.