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birth defects

Birth Defects and the Environment

Birth defects are any anomalies, functional or structural, that present in infancy or later in life and
are caused by events preceding birth, whether inherited, or acquired. Although there has been some
research into how environmental hazards might cause birth defects, there is still much more work that
needs to be done to understand the relationship of the environment to birth defects.

Doctors and public health scientists know how some birth defects happen, and they can, in some
cases, make recommendations to help prevent them. For many other birth defects, however, there
are no clear causes. It is likely that most birth defects happen for many reasons and one of these might be the environment.
There are very few birth defects with a definite link to environmental hazards. However, being able to share data about when and where birth defects happen will help scientists understand whether these defects might be related to the environment. That is one of the main reasons why birth defects are part of the Environmental Public Health Tracking Network.

 In the United States, about three percent of babies are born with birth defects. Some women have a higher chance of having a child with a birth defect. Women over the age of 35 years have a higher chance of having a child with Down syndrome than women who are younger.
If taken when a woman is pregnant, certain drugs can increase the chance of birth defects. Also,
women who smoke and use alcohol while pregnant have a higher risk of having a baby with certain
birth defects. Other women have a higher chance of having a baby with a birth defect because
someone in their family had a similar birth defect.
To learn more about your risk of having a baby with a birth defect, you can talk with a genetic
counselor. Also, to reduce your chances of having a baby with a birth defect, 1) talk with your health
care provider about any medicines that you take, 2) do not drink alcohol or smoke and 3) be sure to take 400 micrograms of the B vitamin folic acid every day. It is the amount of folic acid found in most multivitamins.

On the EPHTN, birth defects are reported as birth prevalence. Birth prevalence is a way to measure how often birth defects happen. It is calculated by counting how many times the birth defect happens in every 10,000 live births. Birth prevalence is the best way to report how often birth defects happen.
Not all states in the U.S. are currently collecting birth defects data. Pennsylvania is among the states that do collect birth defects data. However, not all surveillance systems collect data the same way, so you should not compare information from one state to another. Data on Pennsylvania‘s EPHTN site reflect only data collected on the Certificate of Live Birth.
There will be data about seven types of birth defects in the Pennsylvania EPHTN dataset. All seven birth defects shown on the Pennsylvania EPHTN site are part of the twelve birth defects in the National Birth Defects Prevention Network’s (NBDPN) annual report. The Pennsylvania EPHTN’s lists of birth defects are limited to those reported at the time of birth on the Certificate of Live Birth. Please note that recent and historical studies have verified the under-reporting of birth defects on birth certificates, especially for defects that are not easily diagnosed at birth or soon after.

Overview of Birth Defects

Anencephaly is a condition present at birth that affects the formation of the brain and the skull
bones that surround the head. Anencephaly results in only minimal development of the brain. Often, the brain lacks part or the entire cerebrum (the area of the brain that is responsible for thinking, vision, hearing, touch and movement). There is no bony covering over the back of the head and there may also be missing bones around the front and sides of the head. There is no cure or standard medical treatment for anencephaly; it is a fatal birth defect. Treatment is supportive. 
Spina bifida refers to a group of conditions in which there has been improper development of the spine during embryonic development (from conception up to about the end of the first month of  pregnancy). The term neural tube defect is also used somewhat interchangeably with the term spina bifida. The entire human nervous system develops from a plate of specialized cells that form along the back of the embryo (the fertilized egg in the first stages of development). The edges of this elongated plate curl toward each other, joining in as many as four places to form a tube and then proceeding caudally (toward the bottom), where the end of the spinal cord will form, and cephalad (toward the head), where further specialization will lead to brain development. Spina bifida results from problems during this amazingly complex process and genetic and environmental factors are involved. Defects can be classified as open (spina bifida, encephalocele) or closed (spina bifida occulta, diastematomyelia).
Oral clefts happen when a baby’s lips or palate or both don’t form completely. A cleft lip is a birth defect in which a baby’s upper lip doesn’t form completely and has an opening in it. A cleft palate is a similar birth defect in which a baby’s palate (roof of the mouth) doesn’t form completely and has an opening in it. These birth defects are called oral clefts. Some babies have just a cleft lip. But most babies with a cleft lip also have a cleft palate. Some babies have only a cleft palate, which is called an isolated cleft palate. Oral clefts happen very early in pregnancy. A baby’s lips are formed by about six weeks of pregnancy. A baby’s palate is formed by about 10 weeks of pregnancy.
Hypospadias is a malformation that affects the urethral tube and the foreskin on a male’s penis. The urethra is the tube that carries urine from the bladder to the outside of the body. Hypospadias is a disorder in which the male urethral opening is not located at the tip of the penis. The urethral opening can be located anywhere along the urethra. Most commonly with hypospadias, the opening is located along the underside of the penis, near the tip. Specific treatment for hypospadias is determined by a baby’s overall health, and extent of the condition. Most often, the condition can be repaired with surgery. Usually, the surgical repair is done when a baby is between 6 and 24 months, when penile growth is minimal.
Gastroschisis is a birth defect in which an infant's intestines stick out of the body through a defect on one side of the umbilical cord. Gastroschisis is a type of hernia. Hernia means "rupture.” Babies with this condition have a hole in the abdominal wall, usually on the right side of the umbilical cord. The child's intestines can be easily seen.
Down syndrome is a chromosomal disorder that includes a combination of birth defects. Affected individuals have some degree of mental retardation, characteristic facial features, and often heart defects and other health problems. The severity of these problems varies greatly among affected individuals. Down syndrome is caused by extra genetic material from chromosome 21. Chromosomes are the structures in cells that contain the genes. The term trisomy is used to describe the presence of three chromosomes, rather than the usual matched pair of chromosomes.

Related Links
CDC Birth Defects