Ideally, all girls and women who are in their childbearing years consume at least 400 micrograms of folate daily. Iron and calcium are two important minerals your body needs in extra amounts during the second and third trimesters of your pregnancy. Your health care provider may prescribe extra iron in addition to the amount in your prenatal supplement if lab tests indicate you are anemic . If you don't have enough dairy foods in your diet, you may need an additional calcium supplement. Iron and calcium supplements should not be taken together as calcium will interfere with the absorption of iron.
Some vitamins can be harmful if taken in excess amounts.
Excess intake of vitamin A has been shown to increase the risks of certain birth defects. It is important to discuss any vitamin and mineral supplements you are taking with your health care provider. Weight Gain Weight gain for a pregnant teen is very important. During the second and third trimesters of your pregnancy, you should be gaining about 1 pound each week. If you are gaining much more than this you can increase your chances of being overweight after your pregnancy.