Anemia in Pregnancy: Why Iron Supplements May Fail

Anemia during pregnancy, where hemoglobin levels do not increase despite taking iron supplements?

When I first became pregnant, my hemoglobin level was 11.6.
Around 30 weeks, a blood test showed that my hemoglobin had dropped to 8.8.
The doctor prescribed iron supplements (Iron Chewable Tablets) at a dosage of 100 mg daily.
At 33 weeks, my hemoglobin remained at 8.8, but by 37 weeks, it had dropped again to 8.6.
I feel very discouraged because despite taking iron supplements for 7 weeks, my hemoglobin continues to decrease.
Could this indicate an underlying issue with my body? Will it affect the fetus? Thank you.

chun, 30~39 year old female. Ask Date: 2017/10/19

Dr. Huang Jianzhong reply Obstetrics and Gynecology

At the beginning of the pregnancy, the hemoglobin level was 11.6, but around 30 weeks, a blood test showed that the hemoglobin had dropped to 8.8.
The doctor prescribed iron supplements (Iron Chewable Tablets) at a dosage of 100 mg daily.
At 33 weeks, the hemoglobin remained at 8.8, but by 37 weeks, it had decreased further to 8.6.
I feel very frustrated that after taking iron supplements for 7 weeks, my hemoglobin is still declining.
Does this indicate any issues with my body? Will it affect the fetus?
1.
Iron Deficiency Anemia: Pregnant women are more susceptible to iron deficiency anemia primarily due to the significant increase in blood volume during pregnancy, which raises the demand for iron.
If the pregnant woman does not supplement iron in a timely manner, this can lead to anemia.
It is understood that the maternal requirement for iron during pregnancy is approximately 650 mg, plus an additional 350 mg for fetal growth and development, totaling about 900-1000 mg of iron needed throughout the pregnancy.
This means that the daily requirement for iron is at least around 4 mg.
Since the typical dietary iron intake is only 10-15 mg, and the gastrointestinal absorption rate during pregnancy is only 40%, this does not meet the increased iron demands.
Additionally, chronic blood loss or poor iron absorption prior to pregnancy can also lead to iron deficiency anemia.
2.
Macrocytic Anemia: Macrocytic anemia occurs due to nutritional deficiencies during pregnancy, specifically a lack of folic acid and vitamin B12, which leads to impaired DNA synthesis.
The demand for folic acid increases significantly during pregnancy.
While a normal individual requires only 50-100 μg of folic acid daily, a pregnant woman needs 500-600 μg daily to meet the fetal needs and maintain her own folic acid reserves.
Furthermore, increased excretion, elevated estrogen and progesterone levels, and early pregnancy symptoms can reduce gastrointestinal absorption of folic acid.
Additionally, if the pregnant woman has infections or hyperthyroidism, this can lead to increased consumption of folic acid, resulting in macrocytic anemia.
3.
Effects of Anemia on the Pregnant Woman: If the pregnant woman has only mild anemia, it generally does not have a significant impact on pregnancy and delivery.
However, in cases of severe anemia, when RBC < 1.5×10^12/L, Hb < 50 g/L, and HCT < 0.13, there can be myocardial hypoxia leading to anemic heart disease and heart failure.
Severe anemia during pregnancy can also result in poor uterine contractions, leading to postpartum hemorrhage, and it significantly increases the risk of postpartum infections due to reduced overall body resistance.
4.
Effects of Anemia on the Fetus: Severe anemia during pregnancy can lead to insufficient oxygen and nutrient supply to the fetus, resulting in intrauterine hypoxia, intrauterine growth restriction (IUGR), preterm birth, and stillbirth.
Additionally, since the period from 25 weeks of gestation to 6 months after birth is a critical time for the increase in the number of neural cells, maternal anemia during this time can reduce the baby's iron reserves, affecting the formation of brain cells.
5.
Iron Deficiency Anemia: Iron deficiency anemia is a type of nutritional anemia that typically arises from increased iron requirements during pregnancy coupled with insufficient intake.
If the pregnant woman has low gastric acid secretion, it can affect iron absorption, or if there is chronic blood loss during pregnancy, iron deficiency anemia may occur.
Pregnant women with iron deficiency anemia should follow their doctor's advice regarding iron supplementation and can also consume iron-rich foods that aid in iron absorption, such as animal liver, beef, fish, and black fungus.
However, due to the high iron content in animal liver, it is not suitable for long-term consumption during pregnancy and should be limited to once a week.
6.
Macrocytic Anemia: Macrocytic anemia is caused by nutritional deficiencies during pregnancy, specifically a lack of folic acid and vitamin B12, leading to impaired DNA synthesis.
Reports indicate an incidence rate of 0.5-2.6%.
Pregnant women with macrocytic anemia can undergo folic acid treatment under medical guidance and should consume foods rich in folic acid and vitamin C, such as various green vegetables, sweet oranges, and strawberries.

Reply Date: 2017/10/19

More Info

Anemia during pregnancy is a common concern, particularly as the body undergoes significant changes to support the growing fetus. The normal hemoglobin levels for pregnant women typically range from 11 to 12 g/dL in the first and second trimesters, and slightly lower in the third trimester due to increased blood volume. Your situation, where hemoglobin levels have dropped from 11.6 g/dL to 8.6 g/dL despite taking iron supplements, raises several important considerations.

Firstly, it is essential to understand that iron deficiency anemia is the most common type of anemia during pregnancy. Iron is crucial for the production of hemoglobin, which carries oxygen in the blood. When pregnant, the demand for iron increases significantly due to the needs of the developing fetus and the expansion of maternal blood volume. If iron intake through diet and supplements is insufficient, anemia can develop.

In your case, the fact that your hemoglobin levels have not improved despite taking iron supplements for several weeks could indicate a few potential issues:
1. Absorption Issues: Some individuals may have difficulty absorbing iron due to gastrointestinal conditions such as celiac disease, inflammatory bowel disease, or even the presence of certain medications that can interfere with iron absorption. Additionally, factors such as high calcium intake or consuming iron with foods high in phytates (like whole grains and legumes) can inhibit iron absorption.

2. Inadequate Dosage: While you are taking 100 mg of iron daily, some women may require higher doses to see an improvement in hemoglobin levels. It's worth discussing with your healthcare provider whether an increased dosage or a different formulation might be more effective.

3. Other Nutritional Deficiencies: Anemia can also be caused by deficiencies in other nutrients, such as vitamin B12 or folate. These vitamins are essential for red blood cell production, and a deficiency can lead to a type of anemia that is not responsive to iron supplementation. A complete blood count (CBC) and additional tests can help determine if other deficiencies are present.

4. Underlying Conditions: Conditions such as chronic inflammation, infections, or even hemolysis (the destruction of red blood cells) can lead to anemia. If your body is under stress from an underlying condition, it may not respond adequately to iron supplementation.

5. Pregnancy-Related Factors: The increased blood volume during pregnancy can dilute hemoglobin levels, leading to a condition known as dilutional anemia. This is particularly common in the later stages of pregnancy.

Regarding the potential impact on your fetus, untreated anemia in pregnancy can lead to several complications, including low birth weight, preterm delivery, and increased risk of postpartum anemia. It is crucial to manage anemia effectively to ensure both maternal and fetal health.

To address your concerns, I recommend the following steps:
- Consult Your Healthcare Provider: Discuss your current treatment plan with your doctor. They may suggest further testing to identify the underlying cause of your anemia and adjust your iron supplementation accordingly.

- Dietary Adjustments: Incorporate iron-rich foods into your diet, such as lean meats, beans, lentils, spinach, and fortified cereals. Pairing these with vitamin C-rich foods (like citrus fruits) can enhance iron absorption.

- Monitor Symptoms: Keep track of any symptoms you experience, such as fatigue, weakness, or shortness of breath, and report these to your healthcare provider.

- Follow-Up Testing: Regular monitoring of your hemoglobin levels and overall health is essential during pregnancy. Your doctor may recommend more frequent blood tests to assess your progress.

In conclusion, while it can be disheartening to see hemoglobin levels drop despite taking iron supplements, it is essential to investigate the underlying causes and adjust your treatment plan accordingly. With appropriate management, you can improve your hemoglobin levels and support a healthy pregnancy.

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