Decreasing the Chance of Birth Defects
Healthy Diet
The maxim "You are what you eat" is sterling advice during the first
three months of pregnancy.
Studies of women who had endured starvation during World War II
illustrate the importance of diet early in pregnancy. Contrary to what
researchers expected, it was not the babies born during food deprivation
that had the most malformations, but those conceived during food
deprivation.
One nutrient known to prevent birth defects is folic acid, the B vitamin
Tammy Troutman took before her pregnancy. Folic acid is the chemical form of
folate, which is found in green leafy vegetables, citrus fruits, and
legumes. Folate aids in cell division, and taking extra folic acid reduces a
woman's chance of having a child with spina bifida and other abnormalities
of the spine and brain.
Spina bifida occurs when the vertebrae do not close completely. It is one
of several conditions known as neural tube defects, because the neural tube
is the portion of the embryo that develops into the brain and spinal column.
In very mild cases, spina bifida causes few or minor problems, but in more
severe cases, the spinal cord protrudes through the vertebrae into a sac
outside the child's body. This impairs the child's mobility and other
neurological functions and requires surgery to repair the opening.
To help prevent neural tube defects, the U.S. Public Health Service has
recommended that all women of childbearing age who are capable of becoming
pregnant consume 0.4 milligrams (mg) of folic acid per day. (For pregnant or
lactating women, the daily value increases to 0.8 mg per day.) It is
especially important that women take in sufficient folate before they become
pregnant.
FDA recently published regulations requiring manufacturers to add folic
acid to enriched grain products such as flour, noodles, bread, rolls, buns,
farina, cornmeal, grits, and rice by January 1998.
Although the main challenge in pregnancy is getting enough nutrients, too
much of a good thing is not good for a developing baby, either. Vitamins A
and D are the most notable examples. Both can be toxic at levels higher than
the recommended daily allowance. Such levels are rarely reached through food
intake; however, women taking dietary supplements need to be aware of this
risk and the amount of these vitamins they are taking. Women who take
vitamin and mineral supplements should discuss with a health-care
professional what vitamins are safe to continue taking during pregnancy.
Only a few foods are completely off-limits during pregnancy. These
include raw or undercooked meat, such as "pink-in-the-middle" burgers, and
raw or undercooked seafood. Bacteria from these can cause severe food
poisoning, which is dangerous to a fetus and very unpleasant for the mother.
Soft drinks, coffee, tea, and other caffeinated drinks can be used in
moderation. Although large doses of caffeine have caused skeletal defects in
rats, one or two cups of coffee daily are not considered dangerous for
developing fetuses.
Alcohol should be avoided at all times during pregnancy because it leads
to low birth weight and can cause deformities as well.
According to the March of Dimes, alcohol is the most common known cause
of fetal damage in the country and the leading cause of preventable mental
retardation. Pregnant women who drink alcohol, especially in large amounts,
put their babies at risk for fetal alcohol syndrome, which causes growth
retardation, facial deformities such as a small head, thin upper lip, and
small jaw bone, an underdeveloped thymus gland, and mental deficiencies or
developmental delays.
If a woman has had a glass or two of wine before finding out she was
pregnant, she probably has not harmed her child. But since no one knows the
exact amount of alcohol that is dangerous, it's best to avoid alcohol when
pregnancy is possible.
Healthy Mothers, Healthy Babies
A pregnant woman who has a serious medical condition may face a greater
than normal risk that her child will have a birth defect.
Diabetes, for example, can complicate a pregnancy in many ways. Women who
must take insulin daily to control their blood sugar are three or four times
more likely to have a baby with major birth defects than are other mothers.
That's not to say they should abandon insulin, however. Without it, many
diabetic women and their babies wouldn't survive pregnancy at all.
Birth defects among diabetics can be greatly reduced if women get their
blood sugar levels under control before becoming pregnant and strictly
manage their diets throughout pregnancy. Gestational diabetes, which
develops during pregnancy, can also be harmful to mother and child, but it
can be controlled through diet or medication.
Epilepsy also increases a woman's chance of having a baby with a birth
defect. It's not clear whether the disease itself or the drugs used to
control it cause malformations, but in either case, the woman's neurologist
and obstetrician should work together to find the safest course of treatment
for the epilepsy and pregnancy.
Rubella, toxoplasmosis, cytomegalovirus, and syphilis can cause birth
defects in the infants of women who have these infectious diseases. Rubella
infection during early pregnancy can cause abnormalities of the heart, eyes
and ears. Any woman planning a pregnancy should be tested for rubella
immunity and vaccinated if necessary. She must wait three months after
vaccination before becoming pregnant, however, because the vaccine itself
can endanger a developing fetus.
Toxoplasmosis is transmitted only through raw meat and cat feces, both of
which pregnant women should try to avoid. The disease causes malformations
of the brain, liver and spleen if a fetus becomes infected in the first
trimester.
If a woman has syphilis, she should be treated with antibiotics before
pregnancy. If not treated by at least the fourth month, syphilis can cause
bone and tooth deformities in the baby, as well as nervous system and brain
damage.
Cytomegalovirus (CMV) is a herpes virus that causes no real problem--and
sometimes not even symptoms--for adults and children. In pregnancy, however,
it can damage the fetus' brain, eyes or ears. Because most people contract
the infection, whose symptoms are very much like a cold, when they are
children, most adults are immune to it. Pregnant women who do not know if
they've had CMV and who work with large groups of young children should
discuss the situation with their health-care providers.
Sometimes it is not a disease that causes birth defects, but the
medication used to treat it. Unfortunately, no one knows for certain how
most drugs will affect a developing fetus. Historically, most women of
childbearing age have been excluded from clinical trials of new drugs, and,
although that is changing, drug manufacturers are understandably reluctant
to involve pregnant women in clinical trials for new drugs. Therefore, the
effects of many drugs are not known until they are in wider use after market
approval.
To be on the safe side, a pregnant woman shouldn't take any drug unless
it is absolutely necessary and not until she's checked with her health-care
provider. However, even physicians have little information when prescribing
medication for pregnant women. What is known about most drugs in pregnancy
is based either on animal studies or on reports of problems after the drug
is on the market. To give guidance about pregnancy safety, FDA requires that
manufacturers include in the professional labeling for each drug which one
of several categories, reflecting information from studies available at the
time the label was developed.
Two examples: Taxol (paclitaxel), used to treat ovarian and breast
cancer, may in some instances be appropriate in pregnancy even though it
causes birth defects in animals and is therefore believed to cause fetal
harm in humans. The benefits of its use to fight life-threatening cancers
may outweigh the potential harm to a fetus.
Accutane (isotretinoin) should never be used in pregnancy. It is highly
effective for treating severe cystic acne, but it causes serious birth
defects. There are other drugs available to treat acne, and the disease is
not life-threatening to the mother.
Who Should Paint the Nursery?
Chemicals--whether it's paint in the nursery or exhaust fumes in a
parking garage--have long been suspected of causing birth defects. It's
important for pregnant women to realize that most birth defects are not
caused by a single factor, nor are they usually caused by faint traces of
toxins. Scientists believe it takes a combination of factors to trigger a
congenital malformation.
"Most birth defects have one or more genetic factors and one or more
environmental factors," explains Richard Leavitt, director of science
information at the March of Dimes.
Most of the chemicals a pregnant woman encounters pose little threat
compared with the harm in smoking, drinking alcohol, or eating a poor diet.
"Most environmental exposure is at a low level compared to things you put
in your mouth or inhale purposefully into your lungs," Leavitt says. "Public
health warnings are aimed at the many to help the relatively few avoid a
problem."
Daily, heavy exposure to chemicals may be dangerous, however. If a
pregnant woman must work around fumes or chemicals, such as in a
dry-cleaning business, art studio, or factory, she should use gloves, masks
and adequate ventilation. But if she just gets a whiff of dry-cleaning fluid
while picking up her laundry from the cleaners, there's little need to
worry, Leavitt says.
Some environmental toxins such as lead are best avoided at any time, but
especially during pregnancy. Scraping leaded paint off an old house window,
drinking water from a pipe soldered with lead, or drinking out of decorative
pottery containing lead can all potentially cause lead poisoning--and mental
retardation--in a fetus.
Radiation is also dangerous to developing babies. A pregnant woman who
works in an x-ray department of a hospital must take precautions to avoid
exposure. Elective dental x-rays should be postponed until delivery, and any
nonpregnant woman who has an x-ray should have her reproductive organs
shielded with a lead apron.
Taking hot baths, using saunas, or exercising in hot, humid weather can
raise a woman's core temperature and have the potential to cause birth
defects, especially in the first trimester. Lukewarm baths and moderate
exercise are fine, however.
And what about computers or video display terminals? Although they have
at times been accused of causing harm, there's probably no need to worry.
Recent studies have not found any relationship between computer terminals
and miscarriages.
And as for who should paint the nursery--today's paints don't contain
lead and therefore probably aren't dangerous. But there are other reasons to
find someone else to do this task. The repetitive motion of painting can be
a strain on back muscles already under pressure from the extra weight of
pregnancy, and standing on your feet for hours can make advanced pregnancy
miserable. If someone else can do it, pass this chore along.
Of all the environmental harms, undoubtedly the most harmful is one women
can control--smoking. Although there is no evidence smoking causes birth
defects, it deprives the fetus of oxygen and leads to a number of problems.
If all pregnant women avoided smoking, the United States would see a 5
percent reduction in miscarriages, a 20 percent reduction in
low-birth-weight births, and an 8 percent reduction in premature deliveries
in this country, according to the March of Dimes.
In the Family
Finally, a number of birth defects are inherited. They are usually
triggered when the child inherits a matching pair of disease-causing genes,
one from each parent. This is most often an issue for couples of similar
ethnic or geographic origins.
For example, African-American couples are most at risk for having a child
with sickle cell anemia. According to the March of Dimes, couples of
Ashkenazic Jewish or French Canadian descent may be carriers of Tay-Sachs
disease. People who know of genetic disorders in their families, or those
who have already had one child with a disorder are also at a greater risk,
as are couples who are closely related, such as first cousins. Genetic
testing is available to determine the risk of passing some genetic disorders
to an unborn child. Once a pregnancy begins, prenatal testing is available
to detect a number of disorders, as well.
Some genetic abnormalities, such as Down syndrome (a genetic abnormality
that causes mental retardation, short stature, and flattened features),
increase with the parents' ages. Women over 35 are at higher risk of having
a child with Down syndrome--about 1 in 100 for a 40-year-old, compared to 1
in 10,000 for a 20-year-old mother or 3 in 1,000 for a 35-year-old mother.
And it's not always just the mother's age that matters. An estimated 25
percent of Down syndrome cases can be attributed to increased age of the
father.
Finally, it's important to remember that for most healthy women, the
incidence of birth defects is very low--less than 3 percent. And of
malformations that do occur, the most common are also the most treatable.
Cleft palate and club foot, two of the more common birth defects, can be
surgically repaired. Many heart malformations can be repaired with surgery
so that children live normal lives.
For the most part, health experts say, a woman can do a lot to ensure the
health of her child by maintaining a healthy lifestyle |