Folic acid treats and prevents one type of anemia: the kind caused by low folate. But the most common cause of anemia in pregnancy is low iron, which folic acid doesn’t fix. Knowing which type you have is what makes treatment work.

The short version

  • Anemia means you don’t have enough healthy red blood cells to carry oxygen through your body.
  • Three nutrition-related types: iron deficiency (most common), folate deficiency, and vitamin B12 deficiency. Each needs its own treatment.
  • In pregnancy, iron deficiency is one of the two most common causes, according to the American College of Obstetricians and Gynecologists (ACOG). Your iron need rises to 27 mg a day, and most prenatal vitamins contain that amount.
  • Folic acid’s role: it prevents and treats folate-deficiency anemia, and it protects your baby from neural tube defects. It won’t correct iron-deficiency anemia.
  • Get tested rather than guessing. A blood test tells your provider which type you have.

Three types of anemia, compared

Red blood cells need iron, folate, and vitamin B12 to form properly. A shortage of any one leads to anemia, but the red blood cells look different under a microscope, which is one way your provider tells them apart.

Iron-deficiency anemia Folate-deficiency anemia Vitamin B12-deficiency anemia
What happens to red blood cells Smaller, with less hemoglobin Abnormally large Abnormally large
Common causes Not enough iron in the diet, blood loss (including heavy periods), pregnancy Low-folate diet, heavy drinking, digestive conditions, some medicines, pregnancy Vegetarian or vegan diet, poor absorption (pernicious anemia, stomach surgery), metformin, long-term acid reducers
Treated with Iron Folic acid Vitamin B12 (pills, shots, or nasal gel)
Does folic acid help? No Yes Can improve the blood count while nerve damage continues; B12 is needed

Sources: NIH fact sheets on iron, folate, and vitamin B12.

The large-cell types (folate and B12) are also called megaloblastic anemia. Because they look alike, a folate test is usually ordered together with a B12 test.

Symptoms

Mild anemia often causes no obvious symptoms; your body draws on stored iron and vitamins first, according to the NIH. As it gets worse, all three types share many of the same signs:

  • Tiredness, weakness, and low energy
  • Trouble concentrating or remembering things
  • Shortness of breath
  • A racing or pounding heart
  • Pale skin
  • Headache

Some signs point more toward one type:

  • Iron: stomach upset, feeling cold, and getting sick more often
  • Folate: a sore tongue and shallow sores in the mouth
  • B12: numbness or tingling in the hands and feet, balance problems, and memory or mood changes

Many of these overlap with normal pregnancy or life with a new baby. If you’re more exhausted than seems right, or short of breath doing things that used to be easy, mention it to your provider.

Anemia in pregnancy

During pregnancy, the amount of blood in your body increases, so you need more iron for yourself and your growing baby, according to the NIH. Your needs for folate and B12 go up too.

Nutrient Not pregnant (women 19–50) Pregnant Breastfeeding
Iron 18 mg 27 mg 9 mg
Folate 400 mcg DFE 600 mcg DFE 500 mcg DFE
Vitamin B12 2.4 mcg 2.6 mcg 2.8 mcg

The recommended iron amount drops while breastfeeding, while folate and B12 needs stay higher than before pregnancy.

The risks. Too little iron in pregnancy raises the risk of iron-deficiency anemia for you, and of low birth weight, premature birth, and low iron stores for your baby. It might also affect the baby’s brain development, according to the NIH. Low folate in pregnancy is linked to neural tube defects, low birth weight, and preterm birth.

Testing. Your blood is usually checked for anemia during pregnancy, according to ACOG. If you’re anemic, your provider can order tests to find out whether iron, folate, B12, or something else is the cause.

Prenatal vitamins. Most contain 27 mg of iron, the daily recommended amount in pregnancy, according to ACOG. If you already have iron-deficiency anemia, your provider may recommend a higher dose for a while.

What folic acid can and can’t do

What it does. Folic acid prevents and treats folate-deficiency anemia. Once the cause is addressed, this type of anemia most often responds well to treatment within 3 to 6 months, according to MedlinePlus. In pregnancy, the same daily folic acid that protects against neural tube defects also helps keep up with the higher folate needs of making extra blood.

What it doesn’t do.

  • It doesn’t fix iron-deficiency anemia. If your anemia is from low iron, extra folic acid won’t raise your red blood cell count. You need iron.
  • It can hide B12 deficiency. Large amounts of folic acid can correct the blood count in B12-deficiency anemia while nerve damage continues, according to the NIH. This is why it’s risky to treat suspected anemia with high-dose folic acid on your own.
  • It isn’t a fix for anemia from other causes. Some chronic conditions, such as inflammatory bowel disease or rheumatoid arthritis, cause anemia that improves mainly when the underlying condition is treated, according to the NIH.

Take your prenatal vitamin as usual, and if you’re told you’re anemic, ask which type before changing anything.

Preventing anemia with food and vitamins

The same plate can cover all three nutrients. Good sources, according to the NIH fact sheets:

Nutrient Good food sources
Iron Lean meat, seafood, and poultry; iron-fortified cereals and breads; white beans, lentils, spinach, kidney beans, and peas; nuts and raisins
Folate Dark leafy greens, beans and peas, asparagus, avocado, oranges; folic acid in enriched breads, cereals, pasta, and rice
Vitamin B12 Fish, meat, poultry, eggs, and dairy; fortified cereals and nutritional yeast for plant-based diets

Help your body absorb iron. Iron from plant foods and fortified foods is absorbed less well than iron from meat. You absorb more of it when you eat it with meat, poultry, or seafood, or with vitamin C foods like citrus, strawberries, sweet peppers, tomatoes, and broccoli, according to the NIH. Vegetarians need almost twice as much iron as meat eaters for this reason.

Watch the timing of calcium. Calcium can interfere with iron absorption. If you take separate calcium and iron supplements, take them at different times of day.

Keep iron pills away from children. Accidental overdose of iron-containing products is a leading cause of fatal poisoning in children under 6, according to the NIH. Store prenatal vitamins and iron supplements out of reach.

Don’t overdo it. The upper limit for iron from all sources is 45 mg a day for teens and adults, unless your provider prescribes more for a while to treat a deficiency. High doses can cause stomach upset, constipation, and nausea. People with hemochromatosis, an inherited condition that causes iron buildup, should avoid iron supplements.

Related reading

Sources

This article is for general information and is not a substitute for advice from your health care provider.