Your body changes significantly during pregnancy, and with these changes come increased nutritional requirements. Since your baby develops in different ways at different times, your nutritional requirements vary somewhat throughout your pregnancy. After the third month of pregnancy, your fetus is growing very rapidly and your nutritional needs reflect the increasing needs of your growing baby.
Changing Nutritional Needs
Your nutritional needs during pregnancy are dictated by two factors: your cellular needs and those of your growing baby. Early in pregnancy, your baby requires very little in the way of energy because it is so small. It does, however, have significant vitamin and mineral requirements. Later in pregnancy -- after the end of the third month -- the baby is much larger and requires more calories.
Second and Third Trimester
During the second and third trimester of pregnancy, your baby has finished developing all of its organs, but it's growing and adding a layer of fat under its skin. As such, you need about 300 more calories each day than you needed to support your body prior to pregnancy, explain Drs. Michael Roizen and Mehmet Oz in their book "You: Having A Baby." You also need especially large quantities of iron because your blood volume increases by about 50 percent after the end of the third month of pregnancy.
Components of Diet
Because you need a significant quantity of vitamins and minerals but only a few hundred more calories than usual, your diet after the third month of pregnancy should focus on very nutritionally dense foods, explains Dr. Miriam Stoppard in her book "Conception, Pregnancy and Birth." Fruits and vegetables should form the foundation of your diet, with additional calories each day from whole grains, lean sources of protein and plant-based fats.
How Much To Eat
The best pregnancy diets aren't one-size-fits-all; your nutritional requirements will vary with your activity level and pre-pregnancy weight status. In general, most women need to gain about 25 to 35 lbs. during pregnancy, most of it after the third month, explain Heidi Murkoff and Sharon Mazel in their book "What To Expect When You're Expecting." If you're gaining about a pound a week after the third month, you're eating an appropriate quantity of food.
Prenatal Vitamins
Another important part of a pregnancy diet after the third month is a prenatal vitamin that includes 27 mg of iron, note Roizen and Oz. The vitamins and minerals in the prenatal help to ensure that you're getting everything your cells and your baby's cells need to support growth and healthy pregnancy. The iron is particularly important because it can be hard to get all of the iron you need to increase your blood volume from food alone.
References
- "You: Having A Baby"; Michael Roizen, M.D. and Mehmet Oz, M.D.; 2009
- "Conception, Pregnancy and Birth"; Miriam Stoppard, M.D.; 2008
- "What to Expect When You're Expecting"; Heidi Murkoff and Sharon Mazel; 2008
