Exposure to these by either partner can make it more difficult to become pregnant, and can harm the fetus. Ask your parents if there is a family history of problem pregnancies or birth defects. If you have reason to be concerned about a genetic disorder or inherited disease, you may want to consult a genetics specialist. It's important not to be underweight or overweight during pregnancy. Underweight women tend to have smaller babies, who have more problems during labor and after delivery.
Overweight women are more likely to develop high blood pressure or diabetes during pregnancy.
Don't diet during pregnancy, however, or while you are trying to become pregnant. Studies have shown that birth defects of the spine and brain, such as spina bifida and anencephaly, can occur if the mother does not get sufficient folic acid during the first few weeks of her pregnancy. Folic acid is contained in many foods and in multivitamin supplements. Discuss it with your health care provider. If you have diabetes, make sure it is being treated.