Q&A: Preventing Birth Defects

pregnant woman with doctor

Q: How do I prevent birth defects in my baby?

A: A birth defect is an abnormality of structure,
function or body metabolism (inborn error of body chemistry) presenting
at birth or early childhood that results in physical or mental
disability, or is fatal.  About 120,000 babies (1 in 33) in the United
States are born each year with birth defects. Severe birth defects often
require lifelong medical treatment and can be a major cause of
childhood and adult disability. Birth defects are also the leading cause
of infant mortality.

Genetic and environmental factors, or a combination of these factors,
can cause birth defects. However, the causes of about 70 percent of
birth defects are unknown Birth defects generally are grouped into three
major categories: structural/metabolic, congenital infections, and
other conditions. Heart defects are the most common type of structural
birth defects, affecting one baby in 125. Spina bifida/Neural tube
defects affects one in 2,000 babies.( studies have shown that taking
folic acid has reduced the incidence of this disease by 19%)   Metabolic
disorders are not visible, but can be damaging or even cause death, and
affect one in 3,500 babies. PKU (phenylketonuria) is an example of a
metabolic disorder in which a build up of a protein in the blood results
in brain damage. Fortunately, this disorder can be routinely detected
with newborn screening tests, so affected babies can be placed on a
special diet that prevents mental retardation.

Rubella (German measles) is probably the best known congenital
infection that can cause birth defects. If a pregnant woman is infected
in the first trimester, her baby has a one-in-four chance of being born
with one or more symptoms of congenital rubella syndrome (deafness,
mental retardation, heart defects, blindness). Fortunately, because of
aggressive immunization programs, this syndrome has nearly been
eradicated in the United States.  Sexually transmitted infections in the
mother can also endanger the fetus and newborn. For example, untreated
syphilis can cause stillbirth, newborn death or bone defects. About 350
babies were affected by congenital syphilis in the United States in 2006

Other causes of birth defects include (1) Poorly controlled diabetes
during pregnancy and (2) substance abuse during pregnancy. Women who are
diabetic and whose glucose levels are out of control before pregnancy
are at increased risk for a rare but significant defect called caudal
regression syndrome.  In this syndrome, infants are born with absence of
the tail bone, as well as the pelvis and some vertebrae – resulting in
incontinence and major malformations often leading to death. Substance
abuse in pregnancy is also a cause of birth defects.  For example, fetal
alcohol syndrome (FAS), which affects one baby in 1,000 (about 4,000
babies per year in the United States) and results in mental and physical
birth defects, is common in babies whose mothers are heavy drinkers of
alcohol during pregnancy. FAS is the most common preventable birth
defect in the United States. Babies of mothers who use cocaine early in
pregnancy are also at increased risk of birth defects.

What can you do to prevent a congenital
Sometimes the defects may be inherited and
you would not know in advance unless there is a history of abnormal
children in your family.  If you have such a family history or if you
have already had a child with a birth defect you should visit a
Geneticist to see exactly what risk you may run of having similar
children  born to you and whether the abnormality can be determined by
genetic testing via amniocentesis or chorionic villus testing while you
are pregnant.  However in most cases following a few basic
recommendations will serve you well:

1.  Eat fruits and
vegetables and take folic acid 400 mcg daily BEFORE becoming pregnant

2.  Women who have
diabetes should get their disease under control before becoming pregnant
and then while pregnant continue with the proper diet and meds to stay
in control.

3.  Do not drink any
alcohol before or during pregnancy.

4.  Do not smoke
cigarettes are anything else during pregnancy.

5.  Get early and
comprehensive prenatal care. There are routine test your obstetrician
will do for you to detect problems early.

6.  Do not take any
medications during pregnancy without first discussing them with your

7.  After the infant is
born, allow the infant to have newborn metabolic screening studies
done.  These studies are done routinely in all 50 states and U.S.
Territories unless parents refuse them. They are done on a blood sample
taken from the infant’s heel. These tests detect metabolic disorders
that can cause severe mental retardation and/or death early allowing
them to be diagnosed and often treated.


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