Certain nutrients are absolutely essential and must be consumed in pregnancy. These are folic acid, calcium, vitamin D, protein and iron. Common foods with estimated quantities of these nutrients, are as follows: 1) Folic acid (FA): 800 micrograms (mcg) of folic acid are needed per day. 3/4th cup of a ready-to-eat folic acid fortified cereal has 100-700 mcg of FA. Half cup of boiled spinach has 115 mcg of FA; while one orange contains 52 mcg. Nearly 30 grams of dry roasted peanuts have 41 mcg of FA. 2) Calcium: Recommended intake is 1000 milligrams (mg) of calcium per day. Note that 1 cup of calcium fortified ready-to-eat cereal has 3-1000 mg; 1 cup of skimmed milk has 300 mg; about 170 grams of low-fat yogurt has 235 mg; nearly 30 grams of mozzarella cheese has 222 mg; half cup of boiled spinach has 145 mg and 1 cup of calcium-fortified orange juice has 348 mg of calcium. 3) Vitamin D: Recommended intake is 600 international units or IU per day. Apart from fish, other rich sources include: orange juice – calcium and vitamin D fortified (237 ml contains 100 IU); skimmed milk (237 ml contains 115 IU) and hardboiled egg (one egg contains 44 IU). 4) Protein: Recommended intake is 71 grams per day. Example includes 1 cup of cottage cheese (28 grams of protein). Boneless chicken breast (approx 90 grams) has 26 grams of protein and an equal amount of fish could have 17 grams of protein. In contrast, half cup of boiled lentils contains nearly 9 grams; one cup of skimmed milk contains 8 grams and one hardboiled egg has 6 grams of protein. 5) Iron: Recommended intake is 27 milligrams (mg) per day. Half cup of boiled spinach has nearly 2 mg of iron and an equal quantity of boiled beans (kidney beans) has 3 mg of iron. About 3/4th cup of iron-fortified cereal (like oats) has nearly 30 mg iron. Of course, iron tablets need to be regularly taken.
Reference: Mayo Clinic, USA