Birth defect

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at December 15, 2016
StartDiseasesBirth defect

A birth defect, which is also referred to as a congenital disorder, is any type of medical condition that is present at birth. There are many potential types of birth defects that can arise during fetal development.


Definition & Facts

Structural birth defects occur when a part of the body does not form correctly. Examples include a cleft lip and cleft palate and club foot. Congenital heart defects are the most common types of birth defects, and more than 35,000 babies are born with congenital heart defects in the United States per year. Neural tube defects are another type of structural birth defect.

A functional birth defect occurs when parts of the body or body systems do not function correctly. Examples include certain types of metabolic disorders, autoimmune diseases, Down syndrome, and degenerative disorders (like muscular dystrophy). Fetal alcohol syndrome describes a range of birth defects mostly affecting neurological and cognitive functioning that result from alcohol abuse during pregnancy.

Symptoms & Complaints

The symptoms of birth defects vary wildly because the term can refer to many different conditions. In many cases, the defect is apparent at birth or in previous ultrasounds, but an internal birth defect may cause subtle, undetectable symptoms.

Structural birth defects can result in highly visible symptoms like a missing limb, a club foot that points inward, a hole or bump in the back due to spina bifida, or an opening between the lip and nose due to a cleft palate.

If the structural birth defect is due to sickle-shaped blood cells, a lung defect, or a defect of the heart, it can result in failure to thrive. Instead of growing at a steady rate, the infant may appear weak, tired, and frail.

In some cases, an internal structural abnormality, such as cystic fibrosis, may prevent multiple organ systems from working correctly. They may struggle to breathe or have abnormal heart rhythms.

If a child has a disorder stemming from a chromosomal abnormality such as Down syndrome, they may have a variety of developmental delays and intellectual disabilities.


Birth defects have a variety of possible causes. Birth defects can be caused by a mother's illness during pregnancy; a pregnant mother's exposure to certain chemicals, medications, or environmental toxicants; and genetic factors. Using drugs, smoking tobacco, or drinking alcohol while pregnant greatly increase birth defect risks. Pregnant women who are exposed to certain chemicals, particularly some cleaners, insecticides, fertilizers, or industrial chemicals, have a higher chance of giving birth to a child with birth defects.

Illnesses such as diabetes, lupus, or autoimmune diseases can make a mother more likely to have a child with a birth defect. Medications used to treat certain illnesses may also cause the condition. A lack of adequate maternal nutrition can cause some defects. For example, spina bifida can be caused by a maternal folic acid deficiency. 20 percent of structural birth defects are caused by genetic factors.

Diagnosis & Tests

Many structural abnormalities are diagnosed either before or immediately after birth. A diagnosis for issues like a missing limb can be detected through a physical examination. If the structural defect is something more subtle, such as the curved spine of scoliosis, it may not be diagnosed until later childhood.

Doctors will want to know the mother's medical history, family history, any medication she took while pregnant, and whether or not she used drugs or alcohol during pregnancy.

Congenital heart defects may not be diagnosed until a few weeks or months after birth. They can be diagnosed with an electrocardiogram test (EKG) to check the heart's electrical activity and magnetic resonance imaging (MRI) tests to examine the internal organs. More widespread, chemical defects and metabolic disorders may take longer to diagnose. They often require doctors to rule out more common causes of the symptoms.

Treatment & Therapy

Treatment will depend on the type of defect. Structural birth defects such as cleft palate, spina bifida, or heart defects, can often be fixed with surgery. Though open heart surgery on an infant is risky, it may be necessary in some cases. If the defect will only cause issues later in life, such as scoliosis, doctors may recommend waiting a few years before surgery.

If an important body part is missing or deformed, such as a missing limb or a club foot, a patient may need corrective braces, assistive devices, and physical therapy to move around. Some birth defects, like phenylketonuria will require lifelong treatment to manage conditions. Patients may need a special diet or regular medications. Doctors will work with patients to find a treatment method for each unique case.

Prevention & Prophylaxis

Birth defect prevention mostly relies on avoiding exposure to anything that increases the risk. It is recommended that pregnant women avoid or quit smoking, quit drinking, or quit taking any unnecessary medications. They should also avoid contact or exposure to chemicals, particularly solvents, cleaners, and pesticides, whenever possible.

If a person has a family history of certain genetic disorders and may carry genes that increase birth defect risks, genetic counseling may help them identify their risk of having children with birth defects. Getting proper nutrition and maintaining health during pregnancy can also decrease birth defect risks.