Birth Defects and the Environment
BIRTH DEFECTS ARE A LARGE PUBLIC HEALTH PROBLEM AND ARE ESTIMATED TO AFFECT OVER 150,000 CHILDREN IN AMERICA EVERY YEAR.
Birth defects are any
anomalies, functional or structural, that present in infancy or later in life
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
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,
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
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
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.
ENVIRONMENTAL PUBLIC HEALTH TRACKING NETWORK
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
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.
is a condition present at birth that affects the formation of the brain and the
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 (WITHOUT ANENCEPHALY)
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).
CLEFT LIP AND CLEFT PALATE
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.
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 (TRISOMY
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.