The information provided below is for readers based in the United States of America. Readers outside of the United States of America should seek the information from local sources.

What is anemia?

Anemia in pregnancy occurs when you do not have enough red blood cells in your body. This usually happens for one of three reasons:

  1. your body is not making enough red blood cells
  2. you have a history of heavy bleeding prior to pregnancy (especially heavy periods)
  3. your body is destroying your red blood cells

There are several components that make up the bodys blood:

  • white blood cells- fight infection
  • red blood cells- carry oxygen and remove carbon dioxide
  • platelets- responsible for blood clotting
  • plasma- the fluid portion of the blood

Red cells are made up of hemoglobin, which is created in the bone marrow, a sponge-like tissue inside the bone.

Iron deficiency is the most common cause of anemia in pregnancy. Other causes include folate (a B vitamin), vitamin B12 or vitamin A deficiency, chronic inflammation, parasitic infections, and inherited conditions that include thalassemia, sickle cell anemia, inherited hemolytic anemia, and hemoglobinopathies.

Women who are at higher risk for getting anemia include those who have a diet that is low in iron, have pica (an eating disorder), have a gastrointestinal (GI) disease that affects absorption, have a history of heavy menses, a short interval between pregnancies, or heavy bleeding at the time of delivery.

How common is anemia during pregnancy?

Anemia is very common in the US and affects 16 to 29% of pregnant women. As many as 40% of pregnant women worldwide are affected by anemia.

How is anemia during pregnancy diagnosed?

During pregnancy, all pregnant women in the US are checked for anemia at least twice by using a blood test called the Complete Blood Count or CBC. This is one of the many blood tests that are performed at your first prenatal visit and will provide your health care provider with your hemoglobin value. It will be tested again early in the third trimester, usually with the gestational diabetes screen.

If your hemoglobin levels are low enough, then further testing may be done to determine the cause of the anemia. These tests may include an iron level, a test to determine how well the body is carrying iron, a test to see if the red blood cells look normal, and possibly a test to see if the body is making the normal type of hemoglobin.

Less commonly, women will present to their care provider with symptoms of anemia but since these are similar to normal pregnancy symptoms, anemia can be difficult to diagnose by symptoms alone. Symptoms of anemia include:

  • Fatigue
  • Dizziness
  • Headache
  • Weakness
  • Irritability
  • Exercise intolerance

Does anemia cause problems during pregnancy?

Anemia can cause problems during pregnancy but it depends on the severity of the anemia. Anemia is classified as follows:

  • Mild anemia- hemoglobin levels between 10 and 10.9 g/dL
  • Moderate- hemoglobin levels between 7.0 and 9.9 g/dL
  • Severe anemia- hemoglobin levels less than 7.0 g/dL

Mild anemia does not appear to cause problems for the pregnancy. However, moderate (hemoglobin levels 7.0 9.9 g/dL) and severe anemia (hemoglobin levels less than 7.0 g/dL) have been linked to preterm delivery, maternal death, and a higher risk for serious infections.

Does anemia during pregnancy cause problems for the baby?

Using the anemia classification above, mild anemia does not appear to affect the developing baby. However, moderate and severe anemia have been linked to low-birth-weight, stillbirth, and a higher risk of newborn death.

What to consider about taking medications when you are pregnant or breastfeeding:

You should think about:

  • The risks to yourself and your baby if you do not treat the anemia
  • The risk of not controlling your anemia if you stop taking your medication or if you switch to a different medication
  • The risks and benefits of each medication you use when you are pregnant
  • The risks and benefits of each medication you use when you are breastfeeding

What should I know about using medication to treat anemia during pregnancy?

Oral iron supplements are an extremely effective treatment for iron deficiency anemia. It is usually recommended to take 30 to 60 mg of elemental iron a day, along with 400 micrograms of folic acid. It is important to know that iron preparations differ in the amount of elemental iron they contain. Thirty milligrams (30 mg) of elemental iron can be obtained from a dose of 150 mg of ferrous sulfate or 250 mg of ferrous gluconate.

Iron supplements are often hard for pregnant women to take because of the GI side effects associated with them. Constipation, bloating, nausea, and vomiting commonly occur when taking iron supplements. Since these are already a frequent problem for pregnant women, many women are unable or unwilling to tolerate a worsening of these symptoms. In order to lessen these side effects, some women may find it helpful to start with a low dose of iron and slowly increase it over a few days to weeks. Increasing hydration and fiber in the diet can help prevent constipation but if constipation does develop, then using prune juice or stool softeners can help to improve it. Changing the time of day the iron supplement is taken can help to reduce upset stomach, nausea or vomiting.

In general, iron is poorly absorbed in the GI tract. In order to increase absorption, it is recommended to take it on an empty stomach or 4 hours after or 2 hours before eating anything. It is also recommended to avoid taking it with any kind of antacid; calcium-containing foods, drinks, or supplements; caffeinated drinks; and certain types of antibiotics. Iron is best absorbed if it is taken with either a tablet of ascorbic acid (vitamin C) or orange juice. Iron tablets that are enteric-coated or sustained-release are not recommended because they are inefficient sources of iron.

If you cant tolerate oral iron therapy and your anemia is severe enough, then iron can be given through an IV. For most women, this is a safe and effective alternative to oral therapy; however, rare serious side effects can occur.

Less commonly, blood transfusions may be given to treat women who have hemoglobin levels less than 6 mg/dL and whose babies are showing signs of distress. While each pregnancy needs to be evaluated carefully, signs of distress can include low amniotic fluid, abnormal fetal heart rate, and signs of low blood flow going to the babys brain.

Who should NOT stop taking medication for anemia during pregnancy?

It is not likely that stopping your iron supplement will cause any immediate harm, especially if your anemia is mild, but it may have long term consequences. If you are anemic prior to delivery you will have a higher chance of needing a blood transfusion following delivery, especially if unforeseen complications arise at the time of delivery. You will also recover more slowly from the delivery and feel more tired after having the baby if you are anemic.

There are a number of different types of iron supplements that come in both tablet and liquid forms. Talk with your health care provider to find a form of iron replacement that you are able to tolerate better, rather than just stopping the suppleme
nt completely.

What should I know about choosing a medication for my anemia during pregnancy?

Iron supplements have not been found to cause birth defects and are considered safe for use in pregnancy. So the main goal of therapy is finding the right form of iron supplement with the fewest side effects for you.

You may find Pregistrys expert reports about the medications to treat this condition here. Additional information can also be found in the sources listed below.

What should I know about taking a medication for my anemia when I am breastfeeding?

Iron supplements are safe for use during breastfeeding with no reported problems in nursing infants.

What alternative therapies besides medications can I use to treat my anemia during pregnancy?

You can easily get iron from your diet but, to optimize your iron intake, it is important to understand the different types of iron. Heme iron is absorbed by the body the best and can be found in red meat, poultry, and fish. All are good sources of iron, but it is important to limit your consumption to 8 to 12 ounces of low mercury fish per week. More information about mercury content in different types of fish can be found here.

The other type of iron is non-heme iron, which is not as easily absorbed as heme iron. However, it may still be used as a source of iron, particularly for vegetarians. Sources of non-heme iron include legumes, beans, and certain fruits or vegetables. It is also added to foods that indicate they are iron-fortified or enriched, like cereals. Click here to get more information on iron supplementation and the iron content of different foods. Many people with mild anemia may be able to treat it effectively by adding foods that are high in iron to their diet. However, if you have moderate or severe anemia, then you will also need to take some form of iron supplement in order to get enough iron during pregnancy.

What can I do for myself and my baby when I have anemia during pregnancy?

The best things you can do for yourself and your baby is to eat foods that are high in iron and to find an iron supplement that you are able to consistently take throughout your pregnancy. This will help prevent pregnancy complications that are associated with moderate to severe anemia. It will also help you feel better and have more energy throughout your pregnancy and when you are taking care of your newborn.

Resources for anemia during pregnancy:

For more information about Anemia during and after pregnancy, contact (800-994-9662 [TDD: 888-220-5446]).


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Last Updated: 03-10-2019
General information

It is very common for women to worry about having a miscarriage or giving birth to a child with a birth defect while they are pregnant. Many decisions that women make about their health during pregnancy are made with these concerns in mind.

For many women these concerns are very real. As many as 1 in 5 pregnancies end in a miscarriage, and 1 in 33 babies are born with a birth defect. These rates are considered the background population risk, which means they do not take into consideration anything about the health of the mom, the medications she is taking, or the family history of the mom or the baby’s dad. A number of different things can increase these risks, including taking certain medications during pregnancy.

It is known that most medications, including over-the-counter medications, taken during pregnancy do get passed on to the baby. Fortunately, most medicines are not harmful to the baby and can be safely taken during pregnancy. But there are some that are known to be harmful to a baby’s normal development and growth, especially when they are taken during certain times of the pregnancy. Because of this, it is important to talk with your doctor or midwife about any medications you are taking, ideally before you even try to get pregnant.

If a doctor other than the one caring for your pregnancy recommends that you start a new medicine while you are pregnant, it is important that you let them know you are pregnant.

If you do need to take a new medication while pregnant, it is important to discuss the possible risks the medicine may pose on your pregnancy with your doctor or midwife. They can help you understand the benefits and the risks of taking the medicine.

Ultimately, the decision to start, stop, or change medications during pregnancy is up to you to make, along with input from your doctor or midwife. If you do take medications during pregnancy, be sure to keep track of all the medications you are taking.

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