Anemia occurs in up to one third of women during the 3rd trimester. The most common causes of anemia are
If women have a hereditary anemia (such as sickle cell disease Sickle Cell Disease Sickle cell disease is an inherited genetic abnormality of hemoglobin (the oxygen-carrying protein found in red blood cells) characterized by sickle (crescent)-shaped red blood cells and chronic... read more , hemoglobin S-C disease Hemoglobin C, S-C, and E Diseases Hemoglobin C, S-C, and E diseases are inherited conditions characterized by gene mutations that affect the hemoglobin (the protein that carries oxygen) in red blood cells, causing the cells... read more , or some thalassemias Thalassemias Thalassemias are a group of inherited disorders resulting from an imbalance in the production of one of the four chains of amino acids that make up hemoglobin (the oxygen-carrying protein found... read more ), the risk of problems is increased during pregnancy. If women are at increased risk of having any of these disorders because of race, ethnic background, or family history, blood tests to check for the disorders Genetic Screening Genetic screening is used to determine whether a couple is at increased risk of having a baby with a hereditary genetic disorder. Hereditary genetic disorders are disorders of chromosomes or... read more are routinely done before delivery. Chorionic villus sampling Chorionic Villus Sampling Prenatal diagnostic testing involves testing the fetus before birth (prenatally) to determine whether the fetus has certain abnormalities, including certain hereditary or spontaneous genetic... read more or amniocentesis Amniocentesis Prenatal diagnostic testing involves testing the fetus before birth (prenatally) to determine whether the fetus has certain abnormalities, including certain hereditary or spontaneous genetic... read more may be done to check for these disorders in the fetus.
When anemia develops, the blood cannot carry as much oxygen as it normally does. At first, anemia causes no symptoms or only vague symptoms, such as fatigue, weakness, and light-headedness. Affected women may look pale. If anemia is severe, the pulse may be rapid and weak, women may faint, and blood pressure may be low.
If anemia persists, the following may result:
The bleeding that normally occurs during labor and delivery can dangerously worsen anemia in these women.
Measures to correct anemia during pregnancy depend on the cause (see below).
Whether blood transfusions are needed depends on whether the following occur:
Iron deficiency Iron Deficiency Iron deficiency is a common cause of anemia, a condition in which the number of red blood cells is low. Iron deficiency usually results from loss of blood in adults (including bleeding from... read more is the cause of anemia during pregnancy in about 95% of cases. Iron deficiency anemia is usually caused by
Women normally and regularly lose iron every month during menstruation. The amount of iron lost during menstruation is about the same as the amount women normally consume each month. Thus, women cannot store much iron.
To make red blood cells in the fetus, pregnant women need twice as much iron as usual. As a result, iron deficiency commonly develops, and anemia Iron Deficiency Anemia Iron deficiency anemia results from low or depleted stores of iron, which is needed to produce red blood cells. Excessive bleeding is the most common cause. People may be weak, short of breath... read more often results.
Folate (folic acid) deficiency Folate Deficiency Folate deficiency is common. Because the body stores only a small amount of folate, a diet lacking in folate leads to a deficiency within a few months. Not eating enough raw leafy vegetables... read more may also cause anemia during pregnancy. If folate is deficient, the risk of having a baby with a birth defect of the brain or spinal cord (neural tube defect Neural Tube Defects and Spina Bifida Neural tube defects are a certain type of birth defect of the brain, spine, and/or spinal cord. Neural tube defects can result in nerve damage, learning disabilities, paralysis, and death. The... read more ), such as spina bifida, is increased.
Blood tests can confirm the diagnosis of iron deficiency anemia or folate deficiency anemia.
Anemia can usually be prevented or treated by taking iron and folate supplements during pregnancy. If a pregnant woman has iron deficiency, the newborn is usually given iron supplements. Taking folate supplements before becoming pregnant and during pregnancy reduces the risk of the baby having a neural tube defect.
In addition to causing symptoms of anemia, sickle cell disease Sickle Cell Disease Sickle cell disease is an inherited genetic abnormality of hemoglobin (the oxygen-carrying protein found in red blood cells) characterized by sickle (crescent)-shaped red blood cells and chronic... read more increases the risk of the following during pregnancy:
Infections: Pneumonia Overview of Pneumonia Pneumonia is an infection of the small air sacs of the lungs (alveoli) and the tissues around them. Pneumonia is one of the most common causes of death worldwide. Often, pneumonia is the final... read more , urinary tract infections Urinary Tract Infections During Pregnancy Urinary tract infections are common during pregnancy, probably because the enlarging uterus and hormones produced during pregnancy slow the flow of urine in the tubes that connect the kidneys... read more , and infections of the uterus Postpartum Infections of the Uterus Infections that develop after delivery of a baby (postpartum infections) usually begin in the uterus. Bacteria can infect the uterus and surrounding areas soon after delivery. Such infections... read more are the most common.
High blood pressure: About one third of pregnant women who have sickle cell disease develop high blood pressure during pregnancy High Blood Pressure During Pregnancy High blood pressure (hypertension) during pregnancy is classified as one of the following: Chronic hypertension: Blood pressure was high before the pregnancy. Gestational hypertension: Blood... read more .
Blockage of arteries in the lungs by blood clots (pulmonary embolism Pulmonary Embolism (PE) Pulmonary embolism is the blocking of an artery of the lung (pulmonary artery) by a collection of solid material brought through the bloodstream (embolus)—usually a blood clot (thrombus) or... read more ): This problem may be life threatening.
Problems in the fetus: The fetus may grow slowly or not as much as expected (small for gestational age Small-for-Gestational-Age (SGA) Newborn A newborn who weighs less than 90% of newborns of the same gestational age at birth (below the 10th percentile) is considered small for gestational age. Newborns may be small because their parents... read more ). The fetus may be born prematurely Premature Newborn A premature newborn is a baby delivered before 37 weeks of gestation. Depending on when they are born, premature newborns have underdeveloped organs, which may not be ready to function outside... read more .
A sudden, severe attack of pain, called sickle cell crisis, may occur during pregnancy as at any other time. The more severe that sickle cell disease is before pregnancy, the higher the risk of health problems for pregnant women and the fetus, and the higher the risk of death for the fetus during pregnancy. Sickle cell anemia almost always worsens as pregnancy progresses.
If given regular blood transfusions, women with sickle cell disease are less likely to have sickle cell crises, but they become more likely to reject the transfused blood. This condition, called alloimmunization, can be life threatening. Also, transfusions to pregnant women do not reduce risks for the fetus. Thus, transfusions are used only if one of the following occurs:
If a sickle cell crisis occurs, women are treated as they would be if they were not pregnant. They are hospitalized and given fluids intravenously, oxygen, and drugs to relieve pain. If the anemia is severe, they are given a blood transfusion.