Birth Defects Surveillance

Birth Defects - What are they?

According to the March of Dimes, more than 4,500 different birth defects have been identified and, together, they cause more than 20% of all infant deaths in the United States. Birth defects can affect any organ or body system and they are sometimes difficult to identify. While some birth defects may be easily observable - like a missing or malformed limb - others may be very difficult to recognize, such as a rare metabolic disorder or an internal malformation. Birth defects may become evident at different times - during pregnancy, at birth, in early childhood, or even later in life. Birth defects may be caused by many things: genetic errors, toxic substances, drugs or medications, environmental influences, infections during pregnancy, physical injury to the baby before birth, or by unknown causes. In fact, about two thirds of birth defects have no known cause.

Birth Defects - What is their effect?

Birth defects can cause relatively minor problems, such as an extra finger or a skin birthmark, or major problems, such as severe mental retardation, abnormal growth and development, or death. The majority of infant deaths due to birth defects are caused by heart, respiratory, nervous system, or chromosomal defects. 

In Wisconsin, approximately 2,000 infants are born with a birth defect each year, impacting 3% of all births.  Birth defects are a substantial cause of childhood morbidity and long-term disability and are the fifth leading cause of years of potential life lost.  Birth defects are also expensive.  In Wisconsin, the estimated lifetime cost of birth defects for infants born in a given year exceeds $140 million.

To prevent birth defects, we need to know more about what causes them. To identify causes, we need to know the frequency of individual birth defects and we need to compare the occurrence of specific birth defects to the presence of potential causative factors. 

The Wisconsin Birth Defects Registry (WBDR), established in 2004, is intended to:

• Collect epidemiological data that will make it possible to estimate Wisconsin-specific frequency of birth defects occurrence and geographical distribution.

• Identify possible environmental causes or environmental triggers.

• Formulate prevention strategies as illustrated by recent national research that tied folic acid supplementation to the prevention of neural tube defects.

• Allow tracking of apparent birth defect clusters that may occur geographically, racially/ethnically, or by environmental risks.  Alternately, complete data can identify false clusters and provide reassurance regarding perceived risks.

• Contribute to development of policy and programs regarding current or future need for services.

• Provide families appropriate information and referral to services.

For more information on birth defects:

• Wisconsin Birth Defect Prevention and Surveillance

• Council on Birth Defect Prevention and Surveillance

• Centers for Disease Control and Prevention

• National Birth Defects Prevention Network

Last Revised: July 10, 2008