Anemia is a condition in which blood has a lower-than-normal amount of red blood cells or hemoglobin. [1] Anemia in pregnancy is a decrease in the total red blood cells (RBCs) or hemoglobin in the blood during pregnancy. Anemia is an extremely common condition in pregnancy world-wide, conferring a number of health risks to mother and child. [2] While anemia in pregnancy may be pathologic, in normal pregnancies, the increase in RBC mass is smaller than the increase in plasma volume, leading to a mild decrease in hemoglobin concentration referred to as physiologic (or dilutional) anemia. [3] Maternal signs and symptoms are usually non-specific, but can include: fatigue, pallor, dyspnea, palpitations, and dizziness. [4] There are numerous well-known maternal consequences of anemia including: maternal cardiovascular strain, reduced physical and mental performance, reduced peripartum blood reserves, increased risk for peripartum blood product transfusion, and increased risk for maternal mortality. [5]
Common symptoms are headache, fatigue, lethargy, tachycardia, tachypnea, paresthesia, pallor, glossitis and cheilitis. [6] [7] Severe symptoms include congestive heart failure, placenta previa, abruptio placenta, and operative delivery. [6] [8]
Dilutional anemia: There is an increase in overall blood volume during pregnancy, and even though there is an increase in overall red blood cell mass, the increase in the other parts of the blood like plasma decrease the overall percentage of red blood cells in circulation. [9]
Iron deficiency anemia: this can occur from the increased production of red blood cells, which requires a lot of iron and also from inadequate intake of iron, which increase in pregnancy. [7]
Hemoglobinopathies : Thalassemia and sickle cell disease. [7]
Dietary deficiencies: Folate deficiency and vitamin B12 deficiency are common causes of anemia in pregnancy. Folate deficiency occurs due to diets low in leafy green vegetables, and animal sources of protein. [10] B12 deficiency tends to be more common in individuals with Crohn's disease or gastrectomies. [11]
Cell membrane disorders: Hereditary spherocytosis [7]
Autoimmune causes: lead to the hemolysis of red blood cells (Ex: autoimmune hemolytic anemia). [12]
Hypothyroidism and chronic kidney disease [13] [14]
Parasitic infestations: some examples are hookworm or Plasmodium species [7]
Bacterial or viral infections
Iron deficiency is the most common cause of anemia in the pregnant woman. During pregnancy, the average total iron requirement is about 1200 mg per day for a 55 kg woman. This iron is used for the increase in red cell mass, placental needs and fetal growth. About 40% of women start their pregnancy with low to absent iron stores and up to 90% have iron stores insufficient to meet the increased iron requirements during pregnancy and the postpartum period. [15]
The majority of women presenting with postpartum anemia have pre-delivery iron deficiency anemia or iron deficiency anemia combined with acute blood loss during delivery. [16]
Studies have suggested that severe maternal morbidity (SMM) is increased approximately twofold in antepartum maternal anemia. SMM is defined by maternal death, eclampsia, transfusion, hysterectomy, or intensive care unit admission at delivery. Additional complications may include postpartum haemorrhage, preeclampsia, cesarean delivery, and infections. [17]
Iron deficiency during pregnancy is linked to a number of harmful effects on the fetus such as intrauterine growth restriction, death in utero, infection, preterm delivery and neurodevelopmental damage, which may be irreversible. [18] [19] [20]
The most useful test with which to render a diagnosis of anemia is a low RBC count, however hemoglobin and hematocrit values are most commonly used in making the initial diagnosis of anemia. Testing involved in diagnosing anemia in pregnant women must be tailored to each individual patient. Suggested tests include: hemoglobin and hematocrit (ratio of red blood cells to the total blood volume), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), erythrocyte count (number of red blood cells in the blood), red cell distribution width (RDW), reticulocyte count, and a peripheral smear to assess red blood cell morphology. If iron deficiency is suspected, additional tests such as: serum iron, total iron-binding capacity (TIBC), transferrin saturation, and plasma or serum ferritin may be warranted. It is important to note that references ranges for these values are often not the same for pregnant women. Additionally, laboratory values for pregnancy often change throughout the duration of a woman's gestation. For example, the reference values for what level of hemoglobin is considered anemic varies in each trimester of pregnancy. [21] [9]
- First trimester hemoglobin < 11 g/dL
- Second trimester hemoglobin < 10.5 g/dL
- Third trimester hemoglobin < 11 g/dL
- Postpartum hemoglobin < 10 g/dL
Listed below are normal ranges for important lab values in the diagnosis of anemia. Keep in mind that these ranges might change based on each patient's stage in pregnancy: [7]
- Hemoglobin: Men (13.6-16.9), women (11.9-14.8)
- Hematocrit: Men (40-50%), women (35-43%)
- MCV: 82.5 - 98
- Reticulocyte count: Men (16-130X10^3/microL or X10^9), Women (16-98/microL or X10^9)
Differential using MCV
MCV can be a great measure for differentiating between different forms of anemia. MCV measures the average size of your red blood cells. There are three cut off measurements for MCV. If the MCV is < 80fL it is considered microcytic. If the MCV is from 80 to 100 fL then it is considered a normocytic anemia. If the MCV is > 100 fL it is considered a macrocytic anemia. Some causes of anemia can be characterized by different ranges of MCV depending upon the severity disease. Here are common causes of anemia organized by MCV. [22]
MCV < 80 fL
- Iron deficiency
- Thalassemia
- Anemia of chronic disease or anemia of inflammation
MCV 80 - 100 fL
- Iron deficiency
- Infection
- Hypothyroidism
- Liver disease or alcohol use
- Drug-induced
- Hemolysis
- Vitamin B12 or folate deficiency
MCV > 100 fL
- Vitamin B12 or folate deficiency
- Drug induced
- Liver disease or alcohol use
- Hypothyroidism
- Myelodysplastic Syndromes
Pregnant women need almost twice as much iron as women who are not pregnant do. Not getting enough iron during pregnancy raises risk of premature birth or a low-birth-weight baby. [23] Hormonal changes in the pregnant woman result in an increase in circulating blood volume to 100 mL/kg with a total blood volume of approximately 6000–7000 mL. While red cell mass increases by 15–20% during pregnancy, plasma volume increases by 40%. [24] Hemoglobin levels less than 11 g/dL during the first trimester, less than 10.5 g/dL during the second and third trimesters and less than 10 mg/dL in the postpartum period are considered anemic. [25]
Anemia is a very common complication of pregnancy. A mild form of anemia can be a result of dilution of blood. There is a relatively larger increase in blood plasma compared to total red cell mass in all pregnancies, which results in dilution of the blood and causes physiologic anemia . These changes take place to ensure adequate amount of blood is supplied to the fetus and prepares body for expected blood loss at the time of delivery. [26]
Iron deficiency is the most common cause of non-physiologic anemia. Iron deficiency anemia can be prevented with supplemental oral iron 27–30 mg daily. [27] This dose typically corresponds to the amount of iron found in iron-containing prenatal vitamins. Consult with your medical provider to determine whether additional supplements are needed. Complete routine labs during pregnancy for early detection of iron deficiency anemia. [27]
Iron deficiency anemia can also be prevented by eating iron-rich foods. This includes dark green leafy vegetables, eggs, meat, fish, dried beans, and fortified grains. [28]
This may be only applicable to select individuals.
Vitamin B12: Women who consume strictly vegan diets are advised to take Vitamin B12 supplements; this helps prevent anemia due to low Vitamin B12 levels. [29]
Folic Acid: Folic acid supplement recommended for women with history of documented folate deficiency. Folic acid supplementation also recommended for prevention of neural tube defects in the fetus. [29]
For treatment of iron deficiency anemia in pregnant women, iron supplementation at doses higher than prenatal supplements is recommended. The standard doses of oral iron ranges from 40 mg to 200 mg elemental iron daily. [30] Consult with your medical provider to determine the exact dose needed for your condition, higher than needed doses of iron supplements may sometimes lead to more adverse effects. [21]
Iron supplements are easy to take, however adverse effects in some cases may include gastrointestinal side effects, nausea, diarrhea, and/or constipation. In cases when oral iron supplement is not tolerable, other options include longer intervals between each oral dose, liquid iron supplements, or intravenous iron. [21] Intravenous iron may also be used in cases of severe iron deficiency anemia during second and third trimesters of pregnancy. [31]
Anemias due to other deficiencies such as folic acid or vitamin B12 can also be treated with supplementation as well; dose may vary based on level of deficiency. [32]
Other forms of anemias, such as inherited or acquired anemias prior to pregnancy, will require continuous management during pregnancy as well. [29]
Treatment should target the underlying disease or condition affecting the patient.
According to the WHO estimation, the global prevalence of anemia during pregnancy is over 40%, and the prevalence of anemia during pregnancy in North America is 6%. [36] Prevalence of anemia in pregnancy is higher in developing countries compared to developed countries. 56% of pregnant women from low and middle income countries were reported to have anemia. [37]
Folate, also known as vitamin B9 and folacin, is one of the B vitamins. Manufactured folic acid, which is converted into folate by the body, is used as a dietary supplement and in food fortification as it is more stable during processing and storage. Folate is required for the body to make DNA and RNA and metabolise amino acids necessary for cell division and maturation of blood cells. As the human body cannot make folate, it is required in the diet, making it an essential nutrient. It occurs naturally in many foods. The recommended adult daily intake of folate in the U.S. is 400 micrograms from foods or dietary supplements.
Anemia or anaemia is a blood disorder in which the blood has a reduced ability to carry oxygen. This can be due to a lower than normal number of red blood cells, a reduction in the amount of hemoglobin available for oxygen transport, or abnormalities in hemoglobin that impair its function.
Pernicious anemia is a disease where not enough red blood cells are produced due to a deficiency of vitamin B12. Those affected often have a gradual onset. The most common initial symptoms are feeling tired and weak. Other symptoms may include shortness of breath, feeling faint, a smooth red tongue, pale skin, chest pain, nausea and vomiting, loss of appetite, heartburn, numbness in the hands and feet, difficulty walking, memory loss, muscle weakness, poor reflexes, blurred vision, clumsiness, depression, and confusion. Without treatment, some of these problems may become permanent.
Iron-deficiency anemia is anemia caused by a lack of iron. Anemia is defined as a decrease in the number of red blood cells or the amount of hemoglobin in the blood. When onset is slow, symptoms are often vague such as feeling tired, weak, short of breath, or having decreased ability to exercise. Anemia that comes on quickly often has more severe symptoms, including confusion, feeling like one is going to pass out or increased thirst. Anemia is typically significant before a person becomes noticeably pale. Children with iron deficiency anemia may have problems with growth and development. There may be additional symptoms depending on the underlying cause.
Red blood cell distribution width (RDW), as well as various types thereof, is a measure of the range of variation of red blood cell (RBC) volume that is reported as part of a standard complete blood count. Red blood cells have an average volume of 80–100 femtoliters, but individual cell volumes vary even in healthy blood. Certain disorders, however, cause a significantly increased variation in cell size. Higher RDW values indicate greater variation in size. Normal reference range of RDW-CV in human red blood cells is 11.5–15.4%. If anemia is observed, RDW test results are often used together with mean corpuscular volume (MCV) results to determine the possible causes of the anemia. It is mainly used to differentiate an anemia of mixed causes from an anemia of a single cause.
Megaloblastic anemia is a type of macrocytic anemia. An anemia is a red blood cell defect that can lead to an undersupply of oxygen. Megaloblastic anemia results from inhibition of DNA synthesis during red blood cell production. When DNA synthesis is impaired, the cell cycle cannot progress from the G2 growth stage to the mitosis (M) stage. This leads to continuing cell growth without division, which presents as macrocytosis. Megaloblastic anemia has a rather slow onset, especially when compared to that of other anemias. The defect in red cell DNA synthesis is most often due to hypovitaminosis, specifically vitamin B12 deficiency or folate deficiency. Loss of micronutrients may also be a cause.
Microcytic anaemia is any of several types of anemia characterized by smaller than normal red blood cells. The normal mean corpuscular volume is approximately 80–100 fL. When the MCV is <80 fL, the red cells are described as microcytic and when >100 fL, macrocytic. The MCV is the average red blood cell size.
Complications of pregnancy are health problems that are related to, or arise during pregnancy. Complications that occur primarily during childbirth are termed obstetric labor complications, and problems that occur primarily after childbirth are termed puerperal disorders. While some complications improve or are fully resolved after pregnancy, some may lead to lasting effects, morbidity, or in the most severe cases, maternal or fetal mortality.
Macrocytosis is a condition where red blood cells are larger than normal. These enlarged cells, also known as macrocytes, are defined by a mean corpuscular volume (MCV) that exceeds the upper reference range established by the laboratory and hematology analyzer. Upon examination of a peripheral blood smear under microscope, these macrocytes appear larger than standard erythrocytes. It’s noteworthy that macrocytosis is a common morphological feature in neonatal peripheral blood. The presence of macrocytosis can indicate a range of conditions, from benign, treatable illnesses to more serious underlying disorders.
Nutrition and pregnancy refers to the nutrient intake, and dietary planning that is undertaken before, during and after pregnancy. Nutrition of the fetus begins at conception. For this reason, the nutrition of the mother is important from before conception as well as throughout pregnancy and breastfeeding. An ever-increasing number of studies have shown that the nutrition of the mother will have an effect on the child, up to and including the risk for cancer, cardiovascular disease, hypertension and diabetes throughout life.
Neural tube defects (NTDs) are a group of birth defects in which an opening in the spine or cranium remains from early in human development. In the third week of pregnancy called gastrulation, specialized cells on the dorsal side of the embryo begin to change shape and form the neural tube. When the neural tube does not close completely, an NTD develops.
Folate deficiency, also known as vitamin B9 deficiency, is a low level of folate and derivatives in the body. This may result in megaloblastic anemia in which red blood cells become abnormally large, and folate deficiency anemia is the term given for this medical condition. Signs of folate deficiency are often subtle. Symptoms may include fatigue, heart palpitations, shortness of breath, feeling faint, open sores on the tongue, loss of appetite, changes in the color of the skin or hair, irritability, and behavioral changes. Temporary reversible infertility may occur. Folate deficiency anemia during pregnancy may give rise to the birth of low weight birth premature infants and infants with neural tube defects.
Anisocytosis is a medical term meaning that a patient's red blood cells are of unequal size. This is commonly found in anemia and other blood conditions. False diagnostic flagging may be triggered on a complete blood count by an elevated WBC count, agglutinated RBCs, RBC fragments, giant platelets or platelet clumps due to anisocytosis. In addition, it is a characteristic feature of bovine blood.
Hydroxocobalamin, also known as vitamin B12a and hydroxycobalamin, is a vitamin found in food and used as a dietary supplement. As a supplement it is used to treat vitamin B12 deficiency including pernicious anemia. Other uses include treatment for cyanide poisoning, Leber's optic atrophy, and toxic amblyopia. It is given by injection into a muscle or vein, by pill or sublingually.
Vitamin B12 deficiency, also known as cobalamin deficiency, is the medical condition in which the blood and tissue have a lower than normal level of vitamin B12. Symptoms can vary from none to severe. Mild deficiency may have few or absent symptoms. In moderate deficiency, feeling tired, headaches, soreness of the tongue, mouth ulcers, breathlessness, feeling faint, rapid heartbeat, low blood pressure, pallor, hair loss, decreased ability to think and severe joint pain and the beginning of neurological symptoms, including abnormal sensations such as pins and needles, numbness and tinnitus may occur. Severe deficiency may include symptoms of reduced heart function as well as more severe neurological symptoms, including changes in reflexes, poor muscle function, memory problems, blurred vision, irritability, ataxia, decreased smell and taste, decreased level of consciousness, depression, anxiety, guilt and psychosis. If left untreated, some of these changes can become permanent. Temporary infertility, reversible with treatment, may occur. A late finding type of anemia known as megaloblastic anemia is often but not always present. In exclusively breastfed infants of vegan mothers, undetected and untreated deficiency can lead to poor growth, poor development, and difficulties with movement.
Vitamin B12, also known as cobalamin, is a water-soluble vitamin involved in metabolism. It is one of eight B vitamins. It is required by animals, which use it as a cofactor in DNA synthesis, and in both fatty acid and amino acid metabolism. It is important in the normal functioning of the nervous system via its role in the synthesis of myelin, and in the circulatory system in the maturation of red blood cells in the bone marrow. Plants do not need cobalamin and carry out the reactions with enzymes that are not dependent on it.
The term macrocytic is from Greek words meaning "large cell". A macrocytic class of anemia is an anemia in which the red blood cells (erythrocytes) are larger than their normal volume. The normal erythrocyte volume in humans is about 80 to 100 femtoliters. In metric terms the size is given in equivalent cubic micrometers. The condition of having erythrocytes which are too large, is called macrocytosis. In contrast, in microcytic anemia, the erythrocytes are smaller than normal.
Anemia is a deficiency in the size or number of red blood cells or in the amount of hemoglobin they contain. This deficiency limits the exchange of O2 and CO2 between the blood and the tissue cells. Globally, young children, women, and older adults are at the highest risk of developing anemia. Anemia can be classified based on different parameters, and one classification depends on whether it is related to nutrition or not so there are two types: nutritional anemia and non-nutritional anemia. Nutritional anemia refers to anemia that can be directly attributed to nutritional disorders or deficiencies. Examples include Iron deficiency anemia and pernicious anemia. It is often discussed in a pediatric context.
Nutritional neuroscience is the scientific discipline that studies the effects various components of the diet such as minerals, vitamins, protein, carbohydrates, fats, dietary supplements, synthetic hormones, and food additives have on neurochemistry, neurobiology, behavior, and cognition.
Relatively speaking, the brain consumes an immense amount of energy in comparison to the rest of the body. The mechanisms involved in the transfer of energy from foods to neurons are likely to be fundamental to the control of brain function. Human bodily processes, including the brain, all require both macronutrients, as well as micronutrients.