Birth Defects

Menstuff® has compiled the following information on Birth Defects. January is Birth Defects Prevention Month. According to the March of Dimes, about 150,000 babies are born with birth defects each year in the U.S. What many parents don't realize is that some types of birth defects are treatable and some are entirely preventable. Find out what can be done before and during pregnancy to give your child the best possible start.

Birth Defects
What Are Birth Defects?
What Causes Birth Defects?
Common Birth Defects
Diagnosing Birth Defects
Can Birth Defects Be Prevented?


Birth Defects

If you're like most expecting parents, you probably alternate between fantasies about a healthy baby and worries that your baby will have a health problem. Or perhaps you've been told through prenatal screening that your baby may be born with a birth defect.

Many parents assume that all birth defects are severe or even fatal, but the fact is that many are treatable, often immediately after birth - and sometimes even before the baby is born. It's especially important to know the risk factors involved and what you can do to prevent birth defects. However, it's also important to realize that most children born with congenital defects are born to two healthy parents.

What Are Birth Defects?

Birth defects are defined as abnormalities of structure, function, or body metabolism that are present at birth. These abnormalities lead to mental or physical disabilities or are fatal. There are more than 4,000 different known birth defects ranging from minor to serious, and although many of them can be treated or cured, they are the leading cause of death in the first year of life.

According to the March of Dimes, about 150,000 babies are born with birth defects each year in the United States. The American College of Obstetricians and Gynecologists (ACOG) says that out of every 100 babies born in the United States, three have some kind of major birth defect.

Birth defects can be caused by genetic, environmental, or unknown factors.

Structural or metabolic defects are those that result when a specific body part is missing or formed incorrectly or when there is an inborn problem in body chemistry. The most common type of major structural defects are heart defects, which affect one in 100 babies in the United States. Some other common structural defects include spina bifida and hypospadias, a condition in which the opening of the male urethra (where urine exits from the penis) is in the wrong place. Metabolic defects affect one in 3,500 babies and usually involve a missing or incorrectly formed enzyme (one of the proteins necessary for processing chemical substances in the body). This type of defect can be harmful or even fatal, but doesn't usually cause any visible abnormalities in the child. Metabolic defects include Tay-Sachs disease, a fatal disease that affects the central nervous system, and phenylketonuria (PKU), which affects the way the body processes protein. Both of these defects will be discussed in more detail later in this article.

Defects caused by congenital infections result when a mother gets an infection before or during the pregnancy. Examples of infections that can cause birth defects are rubella (German measles), cytomegalovirus (CMV), syphilis, toxoplasmosis, Venezuelan equine encephalitis, parvovirus, and, rarely, chicken pox. None of these infections affect 100% of babies whose mothers are infected during pregnancy. If the mother is infected during early pregnancy, rubella carries the highest risk for birth defects - approximately 20%.

What Causes Birth Defects?

Most babies with birth defects are born to two parents with no obvious health problems or risk factors. A woman can do everything her doctor recommends to deliver a healthy child and still have a baby with a birth defect.

In fact, according to the March of Dimes, about 60% of birth defects have unknown causes. The rest are caused by environmental or genetic factors, or some combination of the two.

Genetics play a role in some birth defects. Every cell in the body has chromosomes containing genes that determine a person's unique characteristics. One missing or faulty gene can cause a birth defect; this is significant when you consider that we each have about 100,000 genes determining everything from the length of our toes to the color of our eyes.

Where do the faulty genes come from? A child inherits one of each pair of chromosomes (and one of each pair of the genes they contain) from each parent. Sometimes, a disease or defect can occur if only one parent passes along the gene for that disease (even though the child receives a normal gene from the other parent); this is called dominant inheritance and includes birth defects such as achondroplasia (a form of dwarfism) and Marfan syndrome (a disorder characterized by abnormally long fingers, arms, and legs). Some birth defects occur only when both parents (who are healthy) each pass along a faulty gene for the same disease to the child; this is called recessive inheritance and includes conditions such as Tay-Sachs disease or cystic fibrosis. Finally, some boys inherit disorders from genes passed on to them by their mothers. These defects, which include conditions such as hemophilia and color-blindness, are called X-linked because the genes are carried on the X chromosome. Because males have only the one X chromosome they receive from their mothers (females have two X chromosomes - one from each parent), a faulty gene on the X chromosome they receive will cause a problem because they don't have a normal copy of the gene on the other X chromosome that females have.

The number or structure of chromosomes can also cause birth defects. An error during the formation of an egg or sperm can cause a baby to be born with too few or too many chromosomes, or with a damaged chromosome. Birth defects caused by chromosome problems include Down syndrome. The risk of this type of birth defect often increases with the age of the mother.

Environmental causes of birth defects have more to do with the mother's health and exposure to chemicals or diseases. When a mother has certain infections, such as rubella, during pregnancy, it can cause birth defects. Alcohol abuse by the mother causes fetal alcohol syndrome, and certain medications taken by the mother can cause birth defects.

Multifactorial birth defects are caused by a combination of genetic and environmental factors and include neural tube defects and cleft lip and palate.

Although there are steps you can take to prevent birth defects, remember that a birth defect can happen even if you or your partner have no history of birth defects in your families or if you've had healthy children in the past.

Other causes of birth defects include alcohol abuse by the mother and Rh disease, which can occur when the mother's and baby's Rh factors (the "positive" or "negative" part of a person's blood type) are different. Although a few medications can cause problems, of the 200 most commonly prescribed drugs, none is associated with a significant risk of birth defects.

Common Birth Defects

These are among the most common defects, occurring in as many as one in 100 births. The specific cause of most heart defects isn't known, although multiple factors may alter the development of the heart during the first 8 to 9 weeks of fetal growth. Exposure to certain medications (such as the antiseizure drug Dilantin, thalidomide, and chemotherapy drugs) during the first trimester of pregnancy may play a role in causing heart defects. Other causes include maternal alcohol abuse, rubella (German measles) infection, and diabetes during pregnancy.

Talk to your health care provider about ways you can avoid these infections while you're pregnant and what you should do if you're exposed to any of them.

Diagnosing Birth Defects

Routine prenatal screening can do two major things: it can help determine if the mother has an infection or other condition that is dangerous to the fetus, and it can help determine if the fetus has certain birth defects. The list of defects that may be detected through prenatal screening includes:

It's important to remember that screening identifies only the possibility that a baby has a defect. It's possible to give birth to a healthy baby after a screening test shows that a defect may be present. You aren't required to have any prenatal screening; talk to your doctor about any tests he or she thinks you should have and discuss any concerns you have about testing.

Your baby will be tested after birth (with your permission) to screen for certain birth defects that require treatment soon after birth. Exactly what your baby will be tested for varies from state to state (you can ask your health care provider or the hospital nursery which tests your state performs routinely), although all states screen for PKU and congenital hypothyroidism. A new testing technique called tandem mass spectroscopy that can screen for many additional disorders of metabolism on a small blood sample is now being adopted by many state newborn screening programs.

The National Institutes of Health recommend that all African-American babies be tested for sickle cell anemia; about 40 states currently do so. Other disorders that your state may test newborns for include:

If you have a concern about a specific birth defect, you may be able to have your baby tested for it as well. Talk to your health care provider about this before the baby is born.

Can Birth Defects Be Prevented?

Many birth defects can't be prevented; however, there are some common-sense precautions you can take before and during pregnancy.

Before you get pregnant. Women who are planning to become pregnant should make sure their vaccinations are up to date, that they don't have any sexually transmitted diseases, and that they are getting the daily recommended dose of folic acid (which is present in orange juice and green leafy vegetables, or can be taken as a supplement in pill form). One way to ensure that you are getting enough is to start taking prenatal vitamins as soon as you begin trying to conceive. It's generally best to avoid unnecessary medications during pregnancy, so make sure you talk to your doctor about any and all over-the-counter and prescription medicines you're taking before you get pregnant; you'll want to stop taking any that aren't vital to your health. Don't do this without talking to your doctor, however.

If you or your partner have a history of any kind of birth defects in your family, if you've already had a child with a birth defect, or if you are part of a high-risk group (because of your age, ethnic background, or medical history), you might want to consult a genetic counselor before you get pregnant. More is being learned about the genes and other factors involved in birth defects all the time and genetic testing and gene therapy are becoming increasingly viable aspects of prepregnancy planning and pregnancy. A genetic counselor can give you advice about prenatal testing and help you deal with any concerns or fears you might have.

While you're pregnant. The best thing that pregnant women can do to increase their likelihood of having a healthy baby is to make sure they take care of their bodies during pregnancy by:

Talk to your health care provider about other precautions you can take to protect the health of your baby - don't be afraid to ask questions if you're concerned.

Intervention in Over 50% of Births

Less than half of births in NHS hospitals are unassisted, with most women undergoing a Caesarean, induced or a forceps delivery. In some hospitals Caesarean deliveries account for nearly 30 per cent of births – twice the level recommended by the World Health Organization. Doctors are accused of 'meddling' to reduce the effects of staff shortages and to cut the chances of subsequent legal action.
Source: London Daily Mail

Editor's Note:  I was once told that over 90% of births in the five burroughs of New York were caesarean since hospital beds are at a premium. Basically, they scheduled in when you were going to give birth.

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