Iron-deficiency Anemia in Pregnancy Causes, Prevention & Treatment

Iron deficiency is by far the most common cause of anemia in pregnancy, but it’s not the only cause. You could also develop anemia from not getting enough folic acid or vitamin B12, by losing a lot of blood, or from certain diseases or inherited blood disorders such as sickle cell disease.

Your iron requirements go up significantly when you’re pregnant. Iron is essential for making hemoglobin, the protein in red blood cells that carries oxygen to other cells. During pregnancy, the amount of blood in your body increases until you have almost 50 percent more than usual. And you need more iron to make more hemoglobin for all that additional blood. You also need extra iron for your growing baby and placenta.

Unfortunately, most women start pregnancy without sufficient stores of iron to meet their body’s increased demands, particularly in the second and third trimesters. If you get to the point where you no longer have enough iron to make the hemoglobin you need, you become anemic.

Your risk is even higher if you have morning sickness severe enough to cause frequent vomiting, if you’ve had two or more pregnancies close together, if you’re pregnant with more than one baby, if you have an iron-poor diet, or if your pre-pregnancy menstrual flow was heavy.

This is why the amount of iron you need shoots up during pregnancy from 18 to 27 milligrams (mg) per day. Because it’s hard to get enough iron through diet alone, the Centers for Disease Control and Prevention recommend that pregnant women take a daily supplement of 30 mg of elemental iron as a preventive dose. Many prenatal supplements contain that amount.

The treatment for anemia depends on the cause. Iron supplements are not always the answer.

How will I know if I’m anemic?

Your practitioner tests your blood for anemia at your first prenatal appointment. One of these tests (hematocrit) measures the percentage of red blood cells in your plasma. The other (hemoglobin) measures the number of grams of hemoglobin in your blood.

Even if you’re not anemic at the beginning of pregnancy, it’s not uncommon to develop anemia as your pregnancy progresses, so you’ll have another blood test in your late second trimester or early third trimester. It’s normal for your hemoglobin and hematocrit levels to go down somewhat in the second half of pregnancy, when the amount of blood in your body is expanding dramatically and the amount of plasma (the fluid component of blood) increases faster than the number and size of red blood cells – but you don’t want them to dip too low.

If you do become anemic, you might not have any symptoms at all, especially if your condition is mild. Or you might feel tired, weak, and dizzy. (Of course, these are symptoms that many women experience during pregnancy, anemic or not.) You might also notice that you’re paler (especially in your fingernails, the underside of your eyelids, and your lips). Other symptoms include a rapid heartbeat, heart palpitations, shortness of breath, headache, dizziness, irritability, and trouble concentrating.

Finally, some studies have found a link between severe iron-deficiency anemia and cravings for non-food substances such as ice, paper, or clay (a condition known as pica). If you do have these cravings, don’t give in to them, and be sure to tell your healthcare provider.

How is iron-deficiency anemia treated?

If your test indicates that you have iron-deficiency anemia, your practitioner will prescribe an iron supplement. The dose will depend on the severity of your anemia, but it’s likely to be 60 to 120 mg or more of elemental iron daily, in addition to the iron in your prenatal supplement. Follow your practitioner’s instructions – never take more iron than prescribed. 

Note that these doses refer to the amount of elemental iron, or pure iron, in a supplement. Some labels list the amount of ferrous sulfate (a kind of iron salt) instead of or in addition to the amount of elemental iron. A supplement that contains 325 mg of ferrous sulfate, the most commonly used iron supplement, will give you about 60 mg of elemental iron. Others use ferrous gluconate, 300 mg of which yields about 34 mg of elemental iron, or ferrous fumarate, which contains about 106 mg of elemental iron in a 325 mg tablet.

In order to absorb as much of the iron as possible, it’s best to take your iron pills on an empty stomach. Wash them down with water or orange juice (the vitamin C helps with absorption), but not with milk (calcium interferes with absorption). Coffee and tea also hinder absorption.

Within a week or so after starting treatment, you should be producing a lot of new red blood cells and your hemoglobin level will begin to rise. It usually takes just a couple of months for the anemia to resolve, but your caregiver will likely advise you to continue taking iron supplements for several more months so you can replenish your iron stores.

One more important thing to note: Be vigilant about keeping any pills containing iron in childproof containers and away from children. More kids die from iron overdose each year than from any other kind of accidental drug poisoning. In fact, a single adult dose can poison a small child.

Are there any side effects from taking iron supplements?

High levels of iron from supplements can upset your gastrointestinal tract. Most often it leads to constipation, which is already a problem for many pregnant women. If you suffer from constipation, try drinking prune juice. It can help you stay regular ­­– and it’s a good source of iron, as well. Taking a stool softener may be helpful, too.

You may also have heartburn, abdominal discomfort, nausea, vomiting, or, less commonly, diarrhea. Try taking your iron at different times of day to see what works best for you. For example, if the iron irritates your stomach or you suffer from heartburn, you’ll want to avoid taking it at bedtime because lying down afterward may increase your discomfort. On the other hand, if your only complaint is that the iron makes you a bit queasy right after you take it, try downing it near bedtime – perhaps you can sleep through the nausea.

If side effects continue to plague you, talk to your practitioner. You may be able to lessen stomach problems by cutting back and taking less iron, and then gradually building up to the dose you need. Or you may find that taking the iron in divided doses throughout the day helps minimize your discomfort. If these tactics don’t help, you may end up needing to take some or all of your iron with food or trying a time-released formula, which is not ideal in terms of absorption but may be a necessary compromise.

By the way, don’t worry if your stools look darker when you start taking iron. That’s a normal and harmless side effect. Contact your healthcare provider right away if you notice blood in your stool, though.

How does iron-deficiency anemia affect my baby’s health and mine?

Your baby does a good job taking care of his iron needs – he’ll get his share before you do. Still, maternal anemia can affect a baby’s iron stores at birth, increasing his risk for anemia later in infancy.

Iron-deficiency anemia during pregnancy is linked to an increased risk of preterm delivery and low birth weight. It’s also associated with a higher risk of stillbirth or newborn death, so it’s something to take seriously.

Iron-deficiency anemia affects your health as well. It can sap your energy and make it harder for your body to fight infection. And if you’re anemic later in pregnancy, you’re more likely to have problems if you lose a lot of blood when you give birth. You may feel dizzy, have a rapid heart rate, or have other symptoms that require you to stay in the hospital an extra day or two. You’re also more likely to need a blood transfusion. And there’s research suggesting that anemia may even raise your risk of postpartum depression.

What can I do to prevent iron deficiency?

Take your prenatal vitamin and eat a healthy diet that includes plenty of iron-rich foods. Red meat is your best bet, although poultry (dark meat), other meats, and shellfish are good sources, too. Non-animal iron-rich foods include beans, lentils, tofu, raisins, dates, prunes, figs, apricots, potatoes (leave the skin on), broccoli, beets, leafy green vegetables, whole grain breads, nuts and seeds, blackstrap molasses, oatmeal, and iron-fortified cereals. Keep in mind that your body absorbs the iron from animal sources (heme iron) much more readily than the iron from non-animal sources (non-heme iron).

One note of caution: Don’t turn to liver for your iron needs. Liver is best avoided during pregnancy because it contains unsafe amounts of vitamin A, which can cause birth defects.

Nutrients that interfere with your body’s ability to absorb iron

If you’re taking calcium supplements or an antacid that contains calcium, don’t take either one while you’re eating iron-rich foods or at the same time as your iron supplement. Calcium hinders your body’s ability to absorb iron. For that reason, don’t take your supplement with milk. Drink milk between meals, instead.

The same goes for tea and coffee, which contain polyphenols that interfere with the absorption of iron from supplements and plant sources.

Nutrients that help your body absorb iron

Eating or drinking something rich in vitamin C when you take your iron supplement or eat iron-rich plant foods can help your body absorb significantly more non-heme iron. Good vitamin C choices include a glass of orange or tomato juice, a handful of strawberries, sliced bell peppers, or half a grapefruit.

Eating meat and fish (sources of heme iron, which your body absorbs easily) can also improve your absorption of the iron in non-meat foods. For example, a bit of beef in a pot of vegetable chili can help you absorb iron from the vegetables.
It will take some work on your part to correct iron-deficiency anemia, but take heart – Mother Nature will give you a hand. If you’re deficient in iron, you’ll actually absorb more iron from your food than someone with adequate stores.

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