Usually, a woman becomes anemic because her body has too little iron. Iron is a mineral that helps to create red blood cells. Iron deficiency affects half of all pregnant women. The recommended amount of iron you need each day increases during pregnancy from about 18 milligrams (mg) per day to 27 mg per day. Most pregnant women get this amount from eating foods that contain iron and taking prenatal vitamins that contain iron. Some women need to take iron supplements to prevent iron deficiency.

Unless your anemia is severe, it is unlikely to harm your baby. But iron deficiency has been linked to an increased risk of preterm birth and low birthweight.  Anemia can also make you feel more tired than usual during your pregnancy.

What You Can Do to Prevent Anemia
You will probably be tested for anemia at least twice during your pregnancy: during your first prenatal visit and then again between 24 and 28 weeks. If you are anemic, your health care provider may prescribe an iron supplement. You can help lower your risk of anemia by eating foods that contain iron during your entire pregnancy. These foods include:

• Poultry (dark meat)
• Dried fruits (apricots, prunes, figs, raisins, dates)
• Iron-fortified cereals, breads and pastas
• Oatmeal
• Whole grains
• Blackstrap molasses
• Liver and other meats
• Seafood
• Spinach, broccoli, kale and other dark green leafy vegetables
• Baked potato with skin
• Beans and peas
• Nuts and seeds

Foods containing vitamin C can increase the amount of iron your body absorbs. So it's a good idea to include products such as orange juice, tomatoes, strawberries and grapefruit in your daily diet.

Coffee, tea, egg yolks, milk, fiber and soy protein block iron absorption. Try to avoid these when eating iron-rich foods.

Some iron supplements may cause heartburn, constipation or nausea. Here are some tips to avoid or reduce these problems:

• Take the pills with meals.
• Start with small doses and work your way up to the full dose slowly. For example, try taking one pill a day for a few days, then two pills until you aren't bothered by that amount. Increase the number of pills until you're taking the amount your health care provider recommends.
• Try different brands to see which works best for you. Be sure to discuss any changes with your health care provider ahead of time.
• Avoid taking iron pills at bedtime.
• Reduce constipation by drinking more water and by eating more fiber. Fiber is found in whole grain foods, breakfast cereals, fruits and vegetables.