About 3% of babies, or 1 of every 33, are born with a congenital or inherited disorder. Congenital or inherited disorders are problems that happen as a baby develops in the mother's body. A congenital or inherited disorder may affect how the body looks, works, or both. Some congenital or inherited disorders are so serious they can cause a baby to die; others are very minor problems that can be easily repaired. Babies born with congenital or inherited disorders have a greater chance of illness and long-term disability than babies without congenital or inherited disorders.
Not all congenital or inherited disorders can be prevented, but you can take some actions that increase your chance of having a healthy baby. Most congenital or inherited disorders are thought to be caused by a complex mix of genetic, behavioral, and environmental factors. However, for many congenital or inherited disorders, exactly how these factors work together is unclear.
When a woman comes into contact with an environmental hazard early in her pregnancy, it may increase the risk of her baby being born with a congenital or inherited disorder. More research is needed to study the links between environmental hazards and congenital or inherited disorders, which is why congenital or inherited disorders are part of the Environmental Public Health Tracking Network.
It is not known what causes approximately 60% of congenital or inherited disorders. The environment remains a source of great public concern, but few environmental exposures have been well-studied. Most congenital or inherited disorders will likely be explained by a complex interaction between genetics and environmental factors. It is not clear how many congenital or inherited disorders are related to environmental exposures, such as chemicals, drugs, and ionizing radiation.
Some chemicals, including polychlorinated biphenyls (PCBs), dioxins, and pesticides, have been linked to nervous system congenital or inherited disorders and developmental problems such as reduced muscle tone and response. Living near a hazardous waste site has been identified as a possible risk factor for congenital or inherited disorders including:
spina bifida
cleft lip or palate
gastroschisis
hypospadias
chromosomal congenital anomalies such as Down syndrome
some heart and blood vessel defects.
Exposure to disinfection by-products in drinking water such as trihalomethanes, or THM, may increase the risk of some types of congenital or inherited disorders affecting the brain and spinal cord, the urinary tract, and the heart.
Although some research on how environmental hazards might cause congenital or inherited disorders has been done, much more work is needed to understand the relationship between the environment and congenital or inherited disorders.
Doctors and public health scientists know how some congenital or inherited disorders happen and in some cases can make recommendations to help prevent them. But the causes of many other congenital or inherited disorders are unclear. Sharing data about when and where congenital or inherited disorders happen will help scientists understand whether these defects might be related to the environment.
About Congenital and Inherited Disorders Data
The prevalence rate of select congenital or inherited disorders in Iowa counties and statewide by year, race/ethnicity of mother, and age of mother.
If a segment of a population is at higher risk for select congenital or inherited disorders.
To inform the public about select congenital or inherited disorders.
For program planning and evaluation by state and local partners.
Allow for consistent and rapid method for calculating and displaying prevalence at selected geographical areas.
Allow for a better understanding of spatial and temporal patterns of selected congenital or inherited disorders.
These data cannot tell us what causes congenital or inherited disorders, or factors that lead to changes in congenital or inherited disorder rates.
Iowa Public Health Tracking birth defects measures are prevalence rates of 12 selected congenital or inherited disorders per 10,000 live births.
The incidence of congenital or inherited disorders would be the ideal measure for congenital or inherited disorders, but it cannot be determined as it requires information that is difficult to determine, such as the number of conceptions and the number of cases "lost" through fetal deaths (i.e., miscarriages, terminations).
Birth defects data on the Iowa Public Health Tracking portal is provided by the Iowa Registry for Congenital and Inherited Disorders (IRCID). The IRCID was established in 1983 through the joint efforts of the University of Iowa and the Iowa Department of Health and Human Services.
State vital records data for the number of live births, by year.
The Iowa Public Health Tracking portal displays birth defect data from the year 2000 through the most recent year of data available.
The data collection methods utilized by IRCID results in a three or four-year lag period before birth defects data are available on the Iowa Public Health Tracking portal.
The Iowa Registry for Congenital and Inherited Disorders performs active surveillance, which means trained abstractors review medical records to make sure all reported potential cases meet rigorous case definitions established by both Iowa and national experts.
Only live births are included on the Iowa Public Health Tracking portal. Iowa does not publish data that includes stillbirths or pregnancy terminations.
The Congenital or Inherited Disorders Program uses multiple data sources to help ensure that all cases are identified. In addition to the primary case finding source of hospital medical records, they use birth certificates, death certificates, and newborn screening data for case finding.
Quality control and data evaluation efforts are performed annually, including an assessment of completeness, accuracy and timeliness. Because cases may be abstracted through one year of age and then subsequent quality control analysis must be performed, there is a 2-3 year data reporting lag.
These data include information about babies born in Iowa with certain health conditions (Anencephaly, Spina Bifida, Hypoplastic Left Heart Syndrome, Tetralogy of Fallot, Transposition of the Great Arteries, Cleft Lip, Cleft Palate, Hypospadias, Gastroschisis, Upper Limb Reductions, Lower Limb Reductions, Trisomy 21) diagnosed within the first year of life.
Iowa Public Health Tracking congenital or inherited disorder measures are aggregated to include 5 years of data. Because congenital or inherited disorder rates are based on only five years of aggregated data, the rates may be suppressed or vary considerably when compared with data from other states that have been collecting congenital or inherited disorder information for a longer time period.
Ideally, incidence rates would be used instead of birth prevalence to measure congenital or inherited disorders occurrence. The numerator of the incidence would be the number of new cases of birth defect A in an area and time period and the denominator would be the number of conceptions at risk of developing congenital or inherited disorder A in that area and time period. Because the both the number of conceptions is unknown and the number of cases “lost” through spontaneous abortions (as well as terminations and later fetal losses depending on the source of ascertainment for the specific surveillance system), incidence cannot be calculated. Birth prevalence is the only appropriate measure that can be reported for congenital or inherited disorders occurrence.
