Anaemia of pregnancy is a condition where a pregnant woman’s blood doesn’t contain enough healthy red blood cells to carry oxygen to her body and developing baby. During pregnancy, the body produces significantly more blood to support the growing baby, and when iron stores and essential vitamins fall short, anaemia can develop, affecting both mother and child.

Understanding Anaemia of Pregnancy

When a woman becomes pregnant, her body undergoes remarkable changes to support new life. One of the most significant changes happens in the blood. The amount of blood in the body increases by about 20% to 30%, requiring more iron and vitamins to produce haemoglobin, the protein in red blood cells that carries oxygen throughout the body.^[1][2]

This natural increase in blood volume means the body must work harder to produce enough red blood cells. When there aren’t sufficient iron stores or vitamins available, the body cannot keep up with this demand, and anaemia develops. The blood becomes diluted, and although this is a normal part of pregnancy to some extent, it can become problematic if the red blood cell count drops too low.^[1]

Red blood cells are the body’s oxygen delivery system. They pick up oxygen from the lungs and transport it to every tissue and organ, including the placenta and the growing baby. Without enough red blood cells, the body struggles to function properly, and the developing baby may not receive adequate oxygen and nutrients for healthy growth.^[1]

How Common Is Anaemia During Pregnancy?

Anaemia of pregnancy is remarkably common, particularly in certain parts of the world. Globally, it is estimated that 37% of pregnant women are affected by anaemia, making it a major public health concern.^[8] The burden falls most heavily on women in low- and lower-middle income countries, especially those living in rural areas, in poorer households, and those with limited access to education.^[8]

In developing countries, the numbers are particularly striking. Studies show that up to 52% of pregnant women in these regions do not get enough iron, making iron deficiency the leading cause of anaemia during pregnancy.^[1] In a study conducted in Northern Tanzania, researchers found that 18% of pregnant women had anaemia, with 2% experiencing severe forms of the condition.^[6]

Even in developed nations, anaemia remains a significant concern. In the United States, research examining nearly 4 million births revealed that rates of prenatal anaemia vary by ethnicity, with higher prevalence among Black women (22%) and Pacific Islander women (18%), and lower rates among Asian women (11%) and White women (10%).^[14]

It’s important to understand that mild anaemia during pregnancy is considered normal due to the natural dilution of blood that occurs as blood volume expands. However, severe anaemia is not typical and requires medical attention to protect both mother and baby.^[1][2]

What Causes Anaemia During Pregnancy?

The pregnancy itself is actually a primary cause of anaemia. As the blood volume increases dramatically to support the growing baby, the concentration of red blood cells becomes diluted. This physiological change is known as the hydremia of pregnancy, and it results in a natural decrease in the proportion of red blood cells relative to the total blood volume.^[14]

Beyond this natural dilution, several specific nutritional deficiencies can cause anaemia during pregnancy. The most common cause is insufficient iron in the diet or iron stores that were already low before pregnancy began. Iron is essential because it forms the core of every red blood cell, and without adequate amounts, the body simply cannot produce enough healthy blood cells.^[1][4]

The developing baby uses the mother’s red blood cells for its own growth and development, particularly during the last three months of pregnancy. If a woman had good iron stores built up in her bone marrow before becoming pregnant, her body can draw on these reserves during pregnancy. Women without sufficient iron stores are at much higher risk of developing iron-deficiency anaemia.^[3]

Another cause is folate deficiency, which occurs when a woman doesn’t get enough folic acid, a B vitamin that is crucial for producing new cells, including healthy red blood cells. During pregnancy, women need extra folate, and sometimes their diet doesn’t provide enough. Folate is found naturally in foods like green leafy vegetables, but many women still fall short of the recommended amounts.^[4]

Vitamin B12 deficiency is a less common but important cause of anaemia during pregnancy. The body needs vitamin B12 to form healthy red blood cells and protein. This vitamin is found primarily in animal products such as milk, eggs, meat, and poultry. Women who follow strict vegetarian or vegan diets are at greater risk of developing vitamin B12 deficiency, and some may need vitamin B12 injections during pregnancy.^[3][4]

Other less common causes include certain blood disorders that a woman may have had before pregnancy, such as sickle cell anaemia or thalassaemia. Heavy menstrual bleeding before pregnancy can also deplete iron stores, making it harder for the body to meet the increased demands of pregnancy.^[1]

Who Is at Higher Risk?

While all pregnant women face some risk of developing anaemia due to the natural increase in blood volume, certain women are at considerably higher risk. Understanding these risk factors can help women and their healthcare providers take preventive steps early in pregnancy.^[2]

Women who are pregnant with twins, triplets, or more babies face increased risk because the body must produce even more blood to support multiple babies. The iron and vitamin demands are significantly higher in multiple pregnancies, making it more challenging for the body to keep up.^[1][4]

Having pregnancies close together, with minimal time between them, increases risk because the body hasn’t had sufficient time to rebuild its iron stores. Each pregnancy depletes the body’s reserves, and without adequate recovery time, a woman may start her next pregnancy already deficient in iron.^[1][2]

Women who experience severe morning sickness and vomit frequently are at higher risk because they may not be able to keep down iron-rich foods or prenatal vitamins. This prolonged inability to eat properly can lead to nutritional deficiencies, including anaemia.^[1][4]

Women who had heavy menstrual periods before becoming pregnant often enter pregnancy with already depleted iron stores. Each menstrual cycle involves blood loss, and heavy periods over time can significantly drain the body’s iron reserves, leaving little cushion for the increased demands of pregnancy.^[1][2]

Teenage mothers face particular risk because their bodies are still growing and developing, creating additional nutritional demands on top of those required for the pregnancy. Young women who are still in their growth years need more iron for their own development, making it harder to meet the baby’s needs as well.^[4]

Women who don’t consume enough iron-rich foods in their regular diet, whether due to dietary restrictions, food preferences, or limited access to nutritious food, are naturally at increased risk. Those following strict vegetarian or vegan diets may struggle to get enough iron and vitamin B12 from plant-based sources alone.^[3]

Recognising the Symptoms

One of the challenges with anaemia during pregnancy is that many symptoms overlap with normal pregnancy experiences, making it difficult to recognise when something more serious is occurring. In fact, many women with mild anaemia don’t notice any specific symptoms at all, which is why routine blood testing during pregnancy is so important.^[1][2]

The most common symptom of anaemia is persistent fatigue and feeling unusually weak. While tiredness is expected during pregnancy, the exhaustion from anaemia tends to be more profound and doesn’t improve with rest. Women may feel so tired that it becomes difficult to complete daily activities or maintain their normal routines.^[1][4]

Feeling cold, particularly in the hands and feet, is another common sign. When the body doesn’t have enough red blood cells to carry oxygen efficiently, circulation to the extremities may be reduced, causing a persistent feeling of coldness even in warm environments.^[1]

Shortness of breath, especially during normal activities that wouldn’t typically cause breathlessness, can signal anaemia. The body isn’t getting enough oxygen, so even mild exertion may leave a woman feeling winded and needing to catch her breath.^[1][2]

Dizziness or feeling lightheaded is another warning sign, particularly when standing up quickly or after being seated for a while. Some women experience frequent headaches as well. These symptoms occur because the brain isn’t receiving adequate oxygen supply.^[1][4]

Physical changes may also be noticeable. The skin may appear unusually pale, as may the lips, nails, and the undersides of the eyelids. The skin might also bruise more easily than before. Some women develop a sore tongue or notice changes in its appearance.^[1][3]

A rapid or irregular heartbeat can occur as the heart works harder to pump oxygen-depleted blood throughout the body. Women may become aware of their heartbeat or feel like their heart is pounding, especially during activity.^[2][4]

Some women experience difficulty concentrating or thinking clearly. Mental fog or trouble focusing on tasks can be frustrating symptoms of anaemia, as the brain requires substantial oxygen to function optimally.^[2]

A less common but notable symptom is restless legs syndrome, characterised by an uncomfortable, irresistible urge to move the legs, particularly when trying to rest or sleep. This can significantly disrupt sleep quality and add to the overall fatigue.^[1]

In cases of iron deficiency, some women develop unusual cravings for non-food items such as dirt, clay, ashes, or chalk. This condition, called pica, is a distinctive sign that the body is severely lacking in iron.^[9]

How Anaemia Affects Pregnancy and the Baby

Untreated or severe anaemia during pregnancy can have serious consequences for both mother and baby. The developing baby relies entirely on the mother to receive adequate oxygen, iron, vitamin B12, and folic acid. When anaemia is present, this essential supply may be compromised, particularly affecting the baby’s growth during the crucial first trimester.^[1]

Babies born to mothers with anaemia face increased risk of being born prematurely, meaning before 37 complete weeks of pregnancy. Premature birth brings its own set of complications and challenges for the newborn’s health and development. Iron deficiency anaemia during pregnancy is specifically linked to higher rates of preterm delivery.^[2][5]

Low birth weight is another significant concern. Babies whose mothers had anaemia during pregnancy are more likely to be born smaller than expected for their gestational age. These babies may face immediate health challenges and have higher rates of health problems later in life.^[2][5]

If anaemia remains untreated throughout pregnancy, the baby is at higher risk of being born with anaemia as well. Infant anaemia can lead to developmental problems that may affect the child’s growth, learning, and overall health. Some studies suggest a higher risk of infant death immediately before or after birth in pregnant women who have severe iron deficiency anaemia.^[1][5]

For the mother, anaemia increases the burden on her body in multiple ways. It significantly raises the risk of excessive blood loss during labour and delivery. Women who are already anaemic cannot tolerate blood loss as well as those with normal blood counts, and this can lead to the need for blood transfusions.^[2][4]

Anaemic mothers have a harder time fighting off infections, making them more vulnerable to complications both during pregnancy and in the postpartum period. The immune system doesn’t function as effectively when the body is oxygen-deprived, leaving women more susceptible to illness at a time when they need to be healthy to care for their newborn.^[2]

Severe anaemia can lead to other pregnancy complications such as placental abruption, where the placenta separates from the uterine wall prematurely. In extreme cases, severe anaemia may even require admission to intensive care units for the mother.^[14]

It’s important to note that while anaemia can cause pregnancy complications, it does not directly cause miscarriage. However, severe anaemia can create conditions that make pregnancy more difficult and risky for both mother and baby.^[1]

Preventing Anaemia During Pregnancy

Prevention is far easier than treating established anaemia, and good nutrition is the cornerstone of prevention. Starting pregnancy with adequate iron stores makes an enormous difference, which is why nutrition before conception is so important. Women who are planning to become pregnant should focus on building up their iron reserves through diet.^[2][3]

Eating iron-rich foods regularly is essential. Red meat, poultry, and fish contain a form of iron called heme iron, which is more easily absorbed by the body than iron from plant sources. Women who eat meat can most easily increase their iron intake by including these foods more frequently in their diet. A 3-ounce serving of sirloin steak, roast beef, or lean hamburger can provide between 1.6 to 3 milligrams of iron.^[2][20]

For women who don’t eat meat or who want additional iron sources, many plant-based foods contain iron. Dark green leafy vegetables like spinach, kale, and collard greens are excellent choices. Dried beans, lentils, and peas provide both iron and other important nutrients. Fortified cereals can be particularly helpful, as they often contain significant amounts of added iron. Dried fruits such as apricots, raisins, dates, and figs offer iron in a convenient, portable form.^[2][20]

Foods high in vitamin C help the body absorb iron more effectively. Eating citrus fruits like oranges, or fresh raw vegetables alongside iron-rich foods can significantly improve iron absorption. Some women find it helpful to have an orange or glass of orange juice along with their prenatal vitamin to enhance iron uptake.^[20]

Folic acid-rich foods are equally important for preventing folate deficiency anaemia. Dark green leafy vegetables, dried beans, wheat germ, and orange juice are excellent sources of folate. These foods should be included regularly throughout pregnancy.^[2]

Prenatal vitamins play a crucial role in prevention. Healthcare providers prescribe prenatal multivitamins specifically formulated with extra iron and folic acid to meet the increased needs of pregnancy. Taking these vitamins daily as prescribed helps ensure adequate intake of essential nutrients. The recommended intake is at least 27 milligrams of iron each day during pregnancy.^[2][15]

An interesting tip involves cooking methods. Using cast iron pots and pans can actually add up to 80% more iron to food. The iron from the cookware leaches into the food during cooking, providing an easy way to increase dietary iron without changing what you eat.^[20]

For vegetarian and vegan women, extra attention to diet is necessary. Since vitamin B12 is found primarily in animal products, women who don’t consume any animal-derived foods need to ensure they get this vitamin through fortified foods or supplements. Some may need vitamin B12 injections during pregnancy to prevent deficiency.^[3]

Regular prenatal care is essential for prevention. Healthcare providers typically screen for anaemia with a blood test at the first prenatal appointment and often repeat testing later in pregnancy. This routine screening can catch developing anaemia early, when it’s easiest to correct.^[2][15]

How the Body Changes: Understanding the Mechanisms

To understand anaemia of pregnancy, it helps to know what’s happening inside the body during this remarkable time. The changes are both mechanical and biochemical, affecting how blood is produced, distributed, and used throughout the body.^[14]

During normal pregnancy, the bone marrow becomes more active in a process called erythroid hyperplasia. This means the marrow is working harder to produce more red blood cells. In a healthy singleton pregnancy, the red blood cell mass actually increases by 15% to 25%. However, this increase is overshadowed by an even larger expansion of plasma volume, which increases by 40% to 50%.^[14]

This disproportionate increase creates a dilution effect. Imagine adding water to a glass of juice – there’s more liquid overall, but it’s less concentrated. The same thing happens with blood during pregnancy. There are more red blood cells in absolute numbers, but they’re diluted by the much larger increase in plasma, the liquid part of blood. This is why the average haematocrit (the proportion of blood volume made up of red blood cells) decreases from about 38-45% in healthy non-pregnant women to around 34% late in singleton pregnancy, and even lower to about 30% in women carrying multiple babies.^[14]

Despite this dilution, in a healthy pregnancy, the oxygen-carrying capacity of the blood remains normal. The body compensates through various mechanisms, and as long as there are sufficient iron and vitamin stores, the system functions well. The developing baby is supplied with adequate oxygen and nutrients through the placenta.^[14]

The problem arises when iron stores are insufficient. Iron forms the core of haemoglobin molecules, and without enough iron, the body cannot produce adequate amounts of this crucial protein. When haemoglobin levels drop too low, the blood cannot carry sufficient oxygen to meet the needs of both mother and baby.^[1][5]

In folate deficiency, the problem is different but equally serious. Folate is essential for DNA synthesis and cell division. Without adequate folate, the bone marrow cannot produce normal red blood cells. The cells that are produced may be larger than normal and fewer in number, unable to effectively transport oxygen throughout the body.^[4]

Vitamin B12 works closely with folate in the production of red blood cells and in protein synthesis. A deficiency in vitamin B12 impairs the body’s ability to make healthy red blood cells, leading to a type of anaemia that can have serious consequences for both the developing nervous system of the baby and the mother’s health.^[3][4]

After delivery, an interesting physiological event occurs. The blood vessels in the placenta contain a significant amount of maternal blood. When the baby is born and the placenta is delivered, this blood returns to the maternal circulation, causing an immediate increase in blood volume and haematocrit. This autotransfusion effect normally helps compensate for blood loss during delivery.^[14]

In women with severe anaemia, however, this natural compensation may not be sufficient. They have less reserve to tolerate the normal blood loss of delivery, which is why anaemia significantly increases the risks associated with childbirth.^[2]