9
Nutrient Supplementation

Identifying Anemia

Blood Sampling

Blood is drawn for analysis of hemoglobin or hematocrit at the preconception/interconception and first prenatal visits. Venipuncture blood yields the most reproducible results and is recommended, in particular, for confirmatory and follow-up studies after anemia has been detected.

The use of skin puncture blood is acceptable but will result in more false-positive and false-negative values. Use of disposable, spring-loaded lancets is helpful. Make the process quick because a few minutes of anxiety results in a cold, sweaty hand and poor blood flow. To improve accuracy, discard the first drop of blood and do not squeeze the finger because this makes tissue fluids contaminate the blood.

Criteria for Anemia

Hemoglobin and hematocrit values are normally lower in pregnant than in nonpregnant women, and they reach the lowest values during the second trimester of pregnancy. Anemia should be defined using the appropriate cutoff values from Table 1 or 2 in Tab 1 (page 16), after adjusting the cutoff value for high altitude (see Table 3 on the next page), if applicable. The effects of altitude and smoking are additive.



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9 Nutrient Supplementation Identifying Anemia Blood Sampling Blood is drawn for analysis of hemoglobin or hematocrit at the preconception/interconception and first prenatal visits. Venipuncture blood yields the most reproducible results and is recommended, in particular, for confirmatory and follow-up studies after anemia has been detected. The use of skin puncture blood is acceptable but will result in more false-positive and false-negative values. Use of disposable, spring-loaded lancets is helpful. Make the process quick because a few minutes of anxiety results in a cold, sweaty hand and poor blood flow. To improve accuracy, discard the first drop of blood and do not squeeze the finger because this makes tissue fluids contaminate the blood. Criteria for Anemia Hemoglobin and hematocrit values are normally lower in pregnant than in nonpregnant women, and they reach the lowest values during the second trimester of pregnancy. Anemia should be defined using the appropriate cutoff values from Table 1 or 2 in Tab 1 (page 16), after adjusting the cutoff value for high altitude (see Table 3 on the next page), if applicable. The effects of altitude and smoking are additive.

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TABLE 3. Adjustments for Altitudesa   Adjustment Value   Hemoglobin Hematocrit Altitude (feet) (g/dl) (%) 3,000-3,999 +0.2 +0.5 4,000-4,999 +0.3 +1.0 5,000-5,999 +0.5 +1.5 6,000-6,999 +0.7 +2.0 a From CDC.11 To avoid underdiagnosis of anemia at high altitude, add the appropriate value from this table to the cutoff value given in Table 1 or 2 in Tab 1, page 16. Example: A woman living in Denver at an altitude of 5,280 ft and smoking 15 cigarettes per day would have a cutoff value for anemia of 11.8 g hemoglobin/dl during her first trimester: 11.3 + 0.5 for altitude. If her hemoglobin were 11.5 g/dl at 11 weeks of gestation, she would be considered anemic. Indications for Additional Testing Serum Ferritin. Serum ferritin provides an estimate of iron reserves. Consider analysis of serum ferritin to confirm that an anemia is due to iron deficiency, especially if there has been inadequate or no hemoglobin or hematocrit response to iron supplementation. Iron Supplements Iron deficiency is the most common cause of anemia during pregnancy. To prevent iron deficiency anemia, routinely recommend iron supplementation at a low-dose, about 30 mg of elemental iron/day, for non-anemic pregnant women during the second and third

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trimesters. Low-dose iron can be given alone or as part of a multivitamin/mineral supplement of appropriate composition for pregnancy Effective forms of iron include ferrous sulfate, ferrous fumarate, and ferrous gluconate. Liquid and chewable forms are available for women who have trouble swallowing tablets or capsules. These iron preparations may stain teeth, but the stain can be removed by brushing. Recommend taking the supplement at bedtime or between meals with water or juice, not with milk, tea, or coffee. (Fruit juice will not enhance the absorption of iron from supplements, but some women may be more likely to drink fruit juice if advised to do so with a supplement. On the other hand, it is important for a woman to know that water is fine if juice is not available.) For anemic women, start a therapeutic dose of about 60 to 120 mg of elemental iron/day Give 60 mg/day as a single dose or 120 mg/day as two separate doses, between meals and/or at bedtime with water or juice. In addition, to ensure an adequate supply of zinc and copper, recommend a multivitamin/mineral supplement of appropriate composition for pregnancy (see “Suggested Content of Prenatal Vitamin/Mineral Supplements") to be taken with a meal. Side effects of nausea, "stomach" discomfort, constipation, or diarrhea may occur during the first few days. If they persist, try a slow-release iron preparation given with meals. Check the hemoglobin or hematocrit again after 1 month. If the anemia is not improved or resolved, consider other causes of anemia. If the anemia is resolved, lower the dose of iron to 30 mg/day For sample statements about iron supplements, see page 62.

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Suggested Content of Prenatal Vitamin/Mineral Supplements The following is the suggested approximate composition of prenatal multivitamin/mineral supplements for use by women identified to be at high nutritional risk. (See the chart "Indications for Nutrient Supplementation" in Tab 1 for further information.) Iron 30-60 mg Zinc 15 mg Copper 2 mg Calcium 250 mg Vitamin D 10 µg (400 IU) Vitamin C 50 mg Vitamin B6 2 mg Folate 300 µg Vitamin B12 2 µg If vitamin A is included, beta-carotene is preferred over retinol to reduce the risk of toxicity or other adverse reactions. Since calcium and magnesium may interfere with iron absorption, upper limits of 250 and 25 mg/dose, respectively, are recommended as a part of vitamin/ mineral supplements. Some calcium supplements provide less than the recommended 600 mg of elemental calcium per tablet. It is advisable to take calcium supplements (e.g., calcium carbonate) with meals to promote absorption of the calcium.