Birth Defects

Birth defects are structural, functional or metabolic abnormalities present at birth that lead to physical or mental disability. Some birth defects may be fatal. There are more than 4,000 different types of known birth defects, ranging from minor and correctable abnormalities to life-long disabilities or even fatalities. Although many can be treated or cured, birth defects are the leading cause of infant death within the first year of life.

The March of Dimes estimates that about 150,000 babies with birth defects are born annually in the United States. Three out of every 100 babies have some type of major developmental birth defect according to the American College of Obstetricians and Gynecologists (ACOG).

Types of Birth Defects

Structural Birth Defect

A structural birth defect means that a specific body part is missing or improperly formed. The most common major structural birth defects are heart defects, occurring in as many as one in 100 births. They include atrial and ventricular septal defects, patent ductus arteriosus, and aortic or pulmonary valve stenosis, among other congenital abnormalities of the heart.

For example, another type of major structural defect occurs during the first month of pregnancy when the structure that develops into the brain and spinal cord is forming. These are called neural tube defects (NTDs), and they arise when the neural tube does not close completely by the 29th day after conception. Researchers have not found a cause for this birth defect, but it is common for a parent to unnecessarily blame themselves for the defect. The most common forms of NTDs are spina bifida and anencephaly. Spina bifida happens when the spinal column fails to completely close around the spinal cord. Anencephaly occurs when parts of the brain fail to develop. This defect, often confused with a developmental birth defect, occurs in three out of 10,000 births. Structural, functional and metabolic birth defects can usually be treated with surgery; however, in most cases, there are residual and incurable life-long symptoms.

Once one understands what birth defects are, they realize the sheer number of people living with a birth defect is much higher than most realize. For example, many people would not identify a swallowing or digestion problem as a birth defect. Gastrointestinal birth defects are another type of structural defect. These defects can arise anywhere along the gastrointestinal tract, which includes the esophagus, stomach, small and large intestine, rectum and anus. The incomplete or abnormal development of any of the gastrointestinal organs can result in serious problems, including vomiting, problems in swallowing and problems with bowel movements. Some of the more common gastrointestinal developmental birth defects include esophageal atresia, diaphragmatic hernia, pyloric stenosis, Hirschsprung's disease, gastroschisis and omphalocele, anal atresia and bilary atresia. Other common structural defects include cleft lip or cleft palate, club foot, hypospadias, and congenital hip dislocation.

Metabolic Birth Defects

Unlike structural or functional defects, metabolic birth defects involve inborn abnormalities of the body's chemistry and affect about one in every 3,500 babies. This type of defect can involve a body process or chemical pathway or reaction, such as processes that rid the body of waste materials or harmful chemicals. While metabolic birth defects can be harmful and even fatal, they may not cause any outwardly noticeable abnormalities in the child. Examples of metabolic disorders include phenylketonuira (PKU) and congenital hypothyroidism.

Functional or Developmental Birth Defects

Functional or developmental birth defects occur when there is a problem with how a body part or body system works. These developmental birth defects can lead to nervous system or brain problems that result in learning disabilities, mental retardation, behavioral disorders, and speech or language difficulties. Again, most people recognize these problems along with physical deformations as what birth defects are, but fail to recognize less noticeable but often just as debilitating metabolic or internal structural defects. Autism, Down syndrome, Prader-Willi syndrome, Fragile X syndrome, muscular dystrophy and cerebral palsy are some examples of functional or developmental birth defects.

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