Introduction:
Anemia (low hemoglobin levels in the blood), especially iron deficiency anemia, is a fairly common condition seen in millions of pregnant women worldwide. During pregnancy, the requirement for iron increases to support the growing fetus. Therefore, when anemia occurs early in pregnancy, they negatively impact the child’s neurodevelopment. This causes a delay in cognitive development (the development process of human beings to think and reason).
How Does Anemia Occur?
Anemia can occur due to infections (tuberculosis, human immunodeficiency virus), inflammations, and micronutrient deficiencies (iron, vitamin B12). Each of these conditions affects the fetus’s brain development in its way. The most commonly seen anemia in pregnancy is iron deficiency anemia, which occurs due to insufficient bioavailability of iron or due to a total reduction in iron stores. Iron deficiency also occurs with an inadequate intake of iron supplements during pregnancy.
How Does Anemia Affect Pregnancy?
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Iron is essential for the adequate growth of the fetus’s brain in the uterus. Iron helps in oxygen transport, gene expression and regulation, energy metabolism, neurogenesis (the process of forming new neurons), myelination (brain cells produce layers of myelin that acts as insulation for the transmission of electrical impulses), and neurotransmitter systems.
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Iron deficiency disrupts the neurotransmitter system while reducing the global myelination of white matter.
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Iron deficiency during the late fetal and early neonatal (newborn) period mainly affects the hippocampus, the area of the brain important for memory, learning, and cognition (the mental process of understanding senses, experience, and thoughts).
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During the perinatal period (period during pregnancy and after childbirth), iron deficiency causes an altered expression of genes necessary for the development and functioning of the hippocampus.
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Iron deficiency also causes reduced birth weight and gestation periods.
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Even when iron stores were overloaded with iron supplementation, health complications persisted in children whose mothers had iron deficiency during pregnancy, which shows the importance of iron supply to the fetus for its long-term health.
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Newborns with low iron tend to have poor auditory recognition memory at birth, poor performance on general motor and neurocognitive development tests, and poor memory performance until the age of four years.
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Children with low blood ferritin (blood protein that has iron) face academic problems in school and have delayed and impaired immediate record memory and working memory needed for their age.
How Does Maternal Anemia Cause Changes in the Brain Structure of the Offspring?
The mechanism of anemia affecting the brain development of the child is complex. During pregnancy, anemia reduces oxygen consumption and hemoglobin-facilitated delivery during increased metabolic demand and expanded blood volume.
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Maternal anemia before birth (antenatal anemia), even mild, is associated with alterations in children’s brain structure, including smaller volumes of bilateral caudate, putamen, and corpus callosum. However, post-natal child anemia was not associated with altered brain development.
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Bilateral caudate is a neurological condition caused by small arterial disease resulting from cardiac embolism (obstruction that travels from the heart to get lodged in the blood vessel). Behavioral and cognitive abnormalities are associated with the caudate vascular lesion. Smaller volumes of bilateral caudate were noted in children with anemic mothers. Low maternal hemoglobin levels are associated with smaller caudate volume. Children born to mothers with moderate anemia had lower regional volumes than those with mild anemia.
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The putamen is a part of the brain that is round in structure and is located in the forebrain. This area is responsible for learning and motor control, including language functions, cognitive functioning, addiction, and speech delivery.
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The corpus callosum is the primary region of the brain that contains white matter tracts which connect the right and left cerebral hemispheres. The corpus callosum is a region in the brain that is important in transferring and combining information from the cerebral hemispheres to process motor, sensory, and high-level cognitive signals. Any changes in this brain region are associated with a cognitive function deficiency. The corpus callosum of children born to anemic mothers during pregnancy was noted to be smaller than others.
How Can Maternal Anemia Be Prevented?
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A total blood count must be checked and repeated for anemia screening at 28 weeks of pregnancy.
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In case of multiple pregnancies or high-risk mothers, an additional hemoglobin check must be performed near-term.
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Pregnant women must be advised to improve their intake and absorption of iron from food. Rich sources of iron are found in meat, poultry, fish, egg yolk, dry fruits, green leafy vegetables (spinach), beans, lentils, and legumes.
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Taking iron along with vitamin C-rich food like oranges can improve the absorption and intake of iron.
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Use cast iron utensils for cooking.
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Certain naturally occurring components in foods inhibit iron absorption and should not be taken along with iron-rich foods. They include polyphenols in certain vegetables and coffee, tannins in tea, phytates in bran, and calcium from dairy products.
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Weekly iron and folic acid supplements must be given to all women, especially in communities where iron deficiency anemia is a problem.
How Is Maternal Anemia Treated?
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Anemia can be treated with simple interventions like an appropriate diet and iron supplements that increase hemoglobin levels over time.
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No rise in hemoglobin level is noted in the first week following iron therapy. Hemoglobin levels usually rise from the second week onwards, and improvement is noted every week following that.
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Some adverse effects of iron therapy include constipation, occasional diarrhea, and nausea.
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For people who cannot tolerate oral iron, failure of oral therapy, or who need immediate correction of anemia (cases like severe anemia during the last month of pregnancy), iron is administered through an intramuscular (IM) or intravenous (IV) route.
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Some drawbacks of the IM route include pain, myalgia (pain in muscles), arthralgia (pain in joints), and injection site abscesses.
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IV preparations like iron sucrose have fewer side effects and are administered undiluted by slow intravenous injection. They can also be administered through IV infusions.
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Blood transfusion is considered when a patient has decompensated (inability of the heart to maintain circulation) due to a drop in hemoglobin concentration and needs a rapid rise in hemoglobin.
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Packed red cell transfusion (red blood cells separated for transfusion) is indicated for pregnant women with severe anemia close to the due date or if they are at risk of blood loss at delivery.
Conclusion:
Maternal anemia is associated with alterations in children’s brain structure, including smaller volumes of bilateral caudate, putamen, and corpus callosum. Therefore, even in the mild range, anemia has severe consequences for the child’s developing brain. Therefore, implementing effective interventions to prevent and treat maternal anemia is essential for better child health and development outcomes.
