Before you conceived, you needed about 15 milligrams (mg) of iron each
day.
Now you need twice as much, since the volume of blood in your
body increases by nearly half during pregnancy.
If you don't have
enough iron to fuel hemoglobin production for yourself and your baby,
you're likely to develop iron-deficient anemia.
As with most vitamins and minerals, iron is often best gotten from
food. Load up on potatoes, broccoli, raisins, beans, oatmeal, leafy
green vegetables, whole grain breads, lean red meat, shellfish, and
iron-fortified cereals. But even if you eat exceptionally well, you'll
have a hard time getting enough iron.
It's common, therefore, for iron
supplements to be prescribed at some point during pregnancy. Iron
supplements can cause constipation, so try countering the effect by
adding more fiber to your diet. If that doesn't help, ask your
provider whether it makes sense to take a stool softener.
Even if you're not anemic early on, you may become so later. Routine
blood tests you take throughout your pregnancy will verify whether
your hemoglobin levels are normal. If you do become mildly anemic,
don't worry about your baby. Your body will make sure he gets adequate
iron before you do, so you'll be short of iron long before he is.
Generally, your baby will be drawing most dramatically on your iron
reserves by about week 20.
National Geographic - In the Womb
Paralumun New Age Village