Birth Defects, Prevention

A birth defect is an abnormal condition present at birth (congenital). Only 2% to 3% of babies may have a serious birth defect. Some birth defects can be treated with medications. Others can be treated with diet or surgery. Many birth defects can be prevented but some cannot. Death from a birth defect is rare.

Many birth defects can be found through screening during pregnancy. However, screening is not 100% accurate:

  • A test may show positive results for a defect when the child is normal (false positive).

  • A test result may show there is no problem when there really is a defect (false negative).

Some of the screening tests include:

  • An ultrasound.

  • Blood tests for the mother.

  • A test of the chromosomes (chorionic villus sampling).

  • Amniotic fluid testing (amniocentesis).

  • A test of blood taken from the umbilical cord of the fetus (cordocentesis).


Most birth defects have unknown causes. However, some defects have been traced to specific causes, such as:

  • Genetic defects can be caused by abnormal genes or chromosomes. These include:

  • Cystic fibrosis.

  • Sickle cell disease.

  • Tay-Sachs Disease.

  • Fragile X syndrome.

  • Down syndrome.

  • Thalassemia.

  • Infectious diseases. These include:

  • German measles.

  • Cytomegalovirus.

  • Toxoplasmosis.

  • Parvovirus.

  • Chickenpox.

  • Syphilis.

  • Herpes virus.

  • Uncontrolled diabetes before and during pregnancy.

  • Reoccurring convulsions (epilepsy).

  • Chemical agents such as:

  • Alcohol, which can cause lifelong physical and mental disabilities in the baby. This is called fetal alcohol syndrome (FAS).

  • Mercury, which is found in certain fish (shark, swordfish, and tilefish).

  • Lead, which is usually found in paint.

  • Illegal drugs.

  • Cigarette smoke.

  • Certain prescription, over-the-counter, and herbal medications. If you are taking a prescription medication, talk to your caregiver before stopping it.

  • Radiation.

  • Chemotherapy.

  • Lack of folic acid, a B vitamin, before and during pregnancy.

  • Lack of iodine before and during your pregnancy.


  • Age of mother is 35 years or older.

  • Age of father is 50 years or older.

  • Mother with a history of diabetes.

  • Mother with a history of epilepsy.

  • A history of a birth defect in the parents.

  • A previous baby with a birth defect.

  • A family history of a birth defect.


  • See your caregiver as soon as you think you are pregnant.

  • Do not drink alcohol before or during pregnancy.

  • Do not take illegal drugs.

  • Do not smoke before (when possible) and during the pregnancy.

  • Before getting pregnant, begin taking a multivitamin as directed by your caregiver.

  • Take folic acid (0.4 mg) before and during pregnancy. It helps prevent spina bifida and a condition where the brain is undeveloped (anencephaly). Multivitamins usually contain folic acid. It is also found in most breakfast cereals.

  • Follow the directions from your caregiver about taking iodine. Your caregiver may suggest that you take 150 micrograms of iodine before and during your pregnancy. Multivitamins usually contain iodine.

  • Do not take more than 5,000 international units of vitamin A a day.

  • Eat a balanced and nutritious diet.

  • Avoid fish that contain mercury (shark, swordfish, and tilefish).

  • Avoid eating soft cheeses before and during the pregnancy.

  • Talk to your doctor before taking any prescription, over-the-counter, or herbal medications.

  • If there is a history of birth defects in the mother, father, previously born children, or family members, you may wish to have genetic counseling before getting pregnant.

  • If you are diabetic, make sure your diabetes is controlled before and during your pregnancy.

  • Get immunizations before becoming pregnant. You may need to be immunized for German measles, mumps, red measles, chickenpox, hepatitis, and other diseases. Immunizations received when you are pregnant may be harmful to the baby.

  • If you are going to have a baby with a birth defect that will need treatment, try to have your baby at a hospital. That way, doctors, intensive care facilities, and equipment to treat and care for the baby's problem will be available.


  • Understand these instructions.

  • Will watch your condition.

  • Will get help right away if you are not doing well or get worse.