Pregnancy week by week

During pregnancy, the basic principles of healthy eating remain the same — get plenty of fruits, vegetables, whole grains, lean protein and healthy fats. However, a few nutrients in a pregnancy diet deserve special attention. Here's what tops the list.

Folate and folic acid — Help prevent brain and spinal cord conditions present at birth

Folate is a B vitamin that helps prevent serious conditions called neural tube defects that can be present in babies at birth. The lab-made form of folate found in supplements and fortified foods is known as folic acid. Folic acid can help lower the risk of a baby being born too early, before the 37th week of pregnancy. This is called premature birth. Folic acid also can help lower the risk of a baby weighing less than is typical at birth. This is known as having a low birth weight.

How much you need: 400 micrograms (mcg) a day of folate or folic acid before becoming pregnant, and 600 to 1,000 micrograms of folate or folic acid a day throughout pregnancy

Good sources: Fortified cereals are great sources of folic acid. Dark green, leafy vegetables, citrus fruits, and dried beans, peas and lentils are good sources of naturally occurring folate.

Along with making healthy food choices, taking a daily prenatal vitamin can help you get enough of this essential nutrient. It's ideal to start taking a prenatal vitamin at least three months before a pregnancy. Anyone who might become pregnant should take a daily vitamin supplement that has folic acid in it.

Calcium — Strengthen bones

You and your baby need calcium for strong bones and teeth. Calcium also helps nerves, muscles and blood vessels work as they should.

How much you need: 1,000 milligrams (mg) a day; pregnant teenagers need 1,300 mg a day

Good sources: The body absorbs calcium best from dairy products. Other calcium sources include broccoli and kale. Many fruit juices and breakfast cereals are fortified with calcium too.

Vitamin D — Supports bone strength

Vitamin D works with calcium to help build your baby's bones and teeth.

How much you need: 600 international units (IU) a day

Good sources: Fatty fish, such as salmon, is a great source of vitamin D. Other options include fortified milk and orange juice.

Protein — supports growth

Protein is crucial for the growth of your unborn baby, also called a fetus.

How much you need: 71 grams (g) a day

Good sources: Lean meat, poultry, seafood and eggs are great sources of protein. Other options include beans and peas, nuts, seeds, and soy products.

Iron — Helps prevent iron deficiency anemia

The body uses iron to make a protein in red blood cells called hemoglobin. Hemoglobin carries oxygen to the body's tissues. During pregnancy, you need double the amount of iron that people who aren't pregnant need. Your body needs this iron to make more blood to supply oxygen to the fetus.

If you don't get enough iron during pregnancy, that can raise your risk of a condition called iron deficiency anemia. Symptoms of iron deficiency anemia can include headache and extreme tiredness. If this condition becomes serious during pregnancy, it also raises the risk of:

• Premature birth.
• Low birth weight in babies.
• A type of depression that happens after birth in the parent who was pregnant. This is called postpartum depression. Postpartum depression seems most linked with a low amount of stored iron after birth. A blood protein called ferritin stores iron in cells.

How much you need: 27 milligrams (mg) a day

Good sources: Lean red meat, poultry and fish are good sources of iron. Other options include iron-fortified breakfast cereals, beans and vegetables.

Prenatal vitamins usually have iron in them. But healthcare professionals sometimes recommend taking an additional iron supplement.

The iron from animal products, such as meat, is most easily absorbed. To help your body absorb iron from plant sources and supplements, pair them with a food or drink high in vitamin C. Good sources of vitamin C include orange juice, tomato juice and strawberries. If you take iron supplements with orange juice, don't drink the type of orange juice that's fortified with calcium. Calcium is an essential nutrient during pregnancy, but it can lower the amount of iron that the body absorbs.

Supplements — Ask your health care professional

Even if you eat a healthy diet, you can miss out on key nutrients. Taking a daily prenatal vitamin can help fill any gaps. Your healthcare professional may recommend special supplements if you follow a strict vegetarian diet or have a long-term health condition. If you're thinking about taking an herbal supplement during pregnancy, talk with your healthcare professional first. Some herbal supplements might be harmful to your pregnancy.

Mayo Clinic's Ultimate Guide to Pregnancy

This guide offers research-backed advice to help you and your baby experience a healthy pregnancy, written by some of the world's leading medical experts.

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