During pregnancy, your growing baby’s health depends on your own health. While this is an honor, it is also a significant demand on your body, requiring changes in almost every body system. Cardiovascular physiology changes drastically during pregnancy and these changes can contribute to anemia in pregnancy.1 Knowing the causes, risks, treatment options, and prevention strategies for anemia of pregnancy can keep you on the lookout and help keep both mom and baby healthy.
Anemia is defined as the reduced ability of the blood to carry oxygen.1 This is due to a low number of red blood cells, low levels of hemoglobin within the red blood cells, or a low concentration of red blood cells in the blood plasma.2 Hemoglobin is the protein in your red blood cells that binds oxygen and delivers it to cells throughout the body.3 When the hemoglobin falls below 10-11 grams per deciliter, depending on the trimester, anemia in pregnancy can be diagnosed.1.2
Pregnancy places increased demands on the mother’s body and blood, which makes her more susceptible to anemia. There are two main causes of anemia in pregnancy:1.11
Blood volume increases during pregnancy, but plasma volume increases more than red blood cells. Plasma volume increases by almost 50%, but red blood cells only increase by about 18%. Because of this, the concentration of hemoglobin in the blood decreases with dilution, giving you a low relative red blood cell count during pregnancy.1.11 Hematocrit is the concentration of red blood cells compared to the total blood volume, so it is normal to have a somewhat low hematocrit in pregnancy.3.11 This is called normal anemia, which can be considered normal and is thought to be potentially beneficial during pregnancy. The slightly thinner blood due to the lower concentration of red blood cells may facilitate the free flow of blood to the uterus and placenta.1.11
After dilution, low iron in pregnancy is the main cause of anemia of pregnancy.2 During pregnancy, there is an increased demand for nutrients, particularly iron, folic acid and vitamin B12.1.2 In addition to needing more of these nutrients than usual during pregnancy, many women don’t consume enough, don’t absorb what they do consume, and lose more nutrients than usual, hence the recommendation for a folate supplement acid and iron for pregnant women.1
Types of anemia affecting pregnant and postpartum women
Pregnant women can be affected by many types of anemia. However, the most common are iron deficiency anemia and megaloblastic anemia due to folic acid deficiency:1.11
Iron deficiency is the cause of 75% of diagnosed cases of anemia during pregnancy.1 Iron is a building block of hemoglobin, the part of red blood cells that delivers oxygen and removes carbon dioxide. During pregnancy, there is an increase in red blood cell production in order to increase blood volume. If the increased iron requirement is not met through diet and supplementation, a pregnant woman may develop iron deficiency and subsequent anemia.4
Acute blood loss after birth is the main cause of anemia during pregnancy and the postpartum period. This is due to significant blood loss that depletes the body’s iron stores and red blood cells. Postpartum hemorrhage, defined as blood loss greater than 1,000 milliliters within the first 24 hours after delivery, is a major contributor to this condition. It is often accompanied by signs and symptoms of hypovolemia, such as low blood pressure, rapid pulse, and dizziness, further complicating the recovery process for new mothers. Effective management and early intervention are vital to prevent severe anemia and ensure maternal health.11,12
During pregnancy, your baby takes up much of your supply of folic acid and you also absorb it more slowly. Folic acid is a B vitamin that helps produce red blood cells. Without sufficient folate, your body can make too few red blood cells that are too large, oval-shaped, and short-lived. This makes them less efficient at carrying oxygen throughout your body.5
Signs and symptoms
When your organs don’t get enough oxygen due to anemia in pregnancy, you may experience symptoms such as:1.2
- Headache
- Extreme fatigue
- Rapid breathing and heart rate
- Paleness
- Craving for ice or dirt/clay during pregnancy
- Bad breath
- faint
- Inability to exercise
- Depression and anxiety
- Brain fog and poor work performance
When I was anemic, I experienced every one of these symptoms. It’s easy to write them off as normal parts of pregnancy. But if you experience any of the above, your doctor may order a simple blood test to evaluate for anemia. A full blood test is standard in the first trimester and again between 24 and 28 weeks of pregnancy, but you can always ask for another one.2
Pregnancy places increased demands on your body and can have a negative impact. This is why a nutrient-dense diet is especially important. If these requirements are particularly high or you do not meet them with your intake, you may be at a higher risk of developing anemia in pregnancy:1.6
- Inadequate nutrition
- Lack of supplements
- Multiple pregnancy
- A short gap between pregnancies
- Teenage pregnancy
- Frequent vomiting due to morning sickness
- History of anemia or heavy periods
Hemoglobin is built with iron. If you are wondering how to increase hemoglobin, your body must have an adequate supply of iron. Many doctors recommend that all pregnant women take a prenatal vitamin with iron. If you are iron deficient, you may need a separate iron supplement in pregnancy:6
The CDC recommends that all pregnant women start taking iron supplements at the first prenatal visit.13 A pregnant woman with iron deficiency anemia should take a dose of 30-60 milligrams of iron, three to four times a day, for a total of 200-300 milligrams per day.1 As for what helps iron absorption, vitamin C increases the absorption of dietary and supplemental iron, and calcium inhibits iron absorption. So consider taking your iron supplement with an orange, tomato or strawberry and avoid dairy or calcium-enriched orange juice at the same time.6
Iron supplements can cause gastrointestinal side effects such as nausea, vomiting, diarrhea, and constipation. Slow-release iron capsules or liquid iron can reduce these side effects and make it easier for a pregnant woman to take iron supplements.1
When an oral iron supplement is not tolerated or ineffective, your doctor may consider iron infusion in pregnancy. Iron infusions can deliver iron directly into the blood faster than dietary supplements. However, it still takes your body the same amount of time to make red blood cells from iron. While iron infusions bypass the gastrointestinal side effects of oral supplements, there are risks of reaction to the infusion, from allergic reaction to fever and skin discoloration.1
Yes, iron deficiency anemia is associated with low birth weight, preterm birth and perinatal mortality.11 Maternal iron deficiency in pregnancy is also associated with behavioral and brain development problems in children.2 Apart from the risks of anemia for the baby, it also has consequences for the mother. Anemia in pregnancy can increase the chance of cesarean birth, postpartum anemia, need for a blood transfusion during labor, and even postpartum depression.2.6
Sometimes, anemia is unavoidable due to normal blood changes during pregnancy or normal anemia.1 However, good nutrition is the best way to prevent severe anemia in pregnancy. Make sure you are getting enough dietary iron and supplement if necessary.6
Dietary iron is most readily available to the body through animal protein sources, which provide heme iron.7 These include lean red meat, poultry and fish.6
Plant sources of iron are called non-heme. Non-heme iron is less easily absorbed, but is not linked to colon cancer in the same way that heme iron is.7 As for iron-rich vegetables, aim for dark, leafy green vegetables, dried beans and peas, nuts and seeds.6.8 Finally, many breads and breakfast cereals are fortified with non-heme iron.6
While no single food will cause or prevent anemia in pregnancy, there are some foods to look out for to optimize absorption of dietary iron:8
Although dairy is an excellent source of protein and a good choice during pregnancy, you should not consume dairy at the same time as iron. Dairy products contain a high amount of calcium, which prevents the absorption of iron. Therefore, it is better to leave free time to eat dairy and iron at least one hour.8
Tannins found in coffee, tea, beer and red wine can make it harder for the body to absorb iron.8 While you don’t need to eliminate these substances from your diet (although you probably don’t drink a lot of beer and wine while you’re pregnant!), it may be helpful to limit your consumption of iron-rich foods or tannin iron supplements.9
Phytic acid is found in grains, beans, nuts and seeds. This anti-nutrient binds to minerals such as iron to make them unavailable to the body. To significantly reduce the phytic acid content, you can soak your grains (such as rice or oats) in water overnight before draining, rinsing and cooking.10
Management of anemia of pregnancy requires attention and preventive steps for the health of mother and baby. Expectant mothers can prevent and treat anemia by consuming adequate dietary iron and supplementation as needed, treating underlying causes, and optimizing nutrient absorption. Awareness and control of anemia symptoms can make diagnosis and treatment easier, so never be afraid to ask for a blood test if you’re feeling down. With proper care and attention, you can minimize anemia in pregnancy and promote a healthy pregnancy and baby.
