Congenital Conditions and Diseases

Congenital conditions and diseases are present before or at the time of the birth. About 3% to 4% of babies in the U.S. are born with a congenital condition that can affect their physical appearance, development, or function. There are more than 4,000 kinds of congenital conditions, ranging from minor conditions that don’t need treatment to serious ones that require medical care or surgery.

Causes

In most cases, the cause of a congenital condition is unknown. When the cause is determined, it may be environmental, genetic, or a combination of both.

Genetic

During conception, a child gets 46 chromosomes total – 23 from one parent and 23 from the other. Those chromosomes contain the genes that determine your unique characteristics – what you look like, how you’ll grow, and how your body functions.

If an error occurs during this process, your child might have the wrong number of chromosomes or a damaged chromosome, causing a congenital condition. Down syndrome is an example of a congenital condition caused by an extra chromosome.

Sometimes even with the right number of chromosomes, a gene on the chromosome is abnormal. For some conditions, like cystic fibrosis, a child gets the same defective gene from both parents. In other conditions, like Marfan syndrome, only one parent passes on an abnormal gene.

Environmental

With an environmental cause, the baby is exposed to something during pregnancy that caused a congenital condition. That could include an infection or chemicals that affect the fetus during a critical stage of development. 

Infections in a pregnant person can cause serious congenital conditions in the fetus, especially during the first nine weeks of pregnancy. Those infections include:

• Toxoplasmosis
• Cytomegalovirus
• Chicken pox
• Rubella

The Zika virus, which is spread by mosquitos, has caused outbreaks in some countries and can cause a birth defect called microcephaly. 

Drinking alcohol during pregnancy may cause fetal alcohol syndrome, which can cause brain damage and growth problems. Some medications can also lead to birth defects when taken during pregnancy.

Diagnosis

Congenital diseases can sometimes be diagnosed before a baby is born. Knowing if a baby has a congenital condition or is at-risk for one can help parents and healthcare providers to plan for medical care after birth.

Prenatal tests may include ultrasound, amniocentesis, or chronic villus sampling. Blood tests may also be done to screen for any risk of specific birth defects like Down syndrome and spina bifida. In some cases, a genetic test may be ordered before birth to help determine the risk of a condition.

For example, if one parent has the gene for cystic fibrosis then the other may be tested as well, since both parents must be carriers for their child to be at-risk. Tests may also be ordered to determine if a pregnant person has an infection or other medical condition that could be harmful to the fetus.

After birth, congenital conditions may be diagnosed through physical examination or blood tests. In the U.S., those screenings may vary from state to state, but all states test newborns for phenylketonuria (PKU), sickle cell disease, congenital hypothyroidism, and about 30 other conditions.

Treatment

Treatment for congenital conditions varies greatly depending on the diagnosis. It may include medication to manage symptoms and prevent complications, or it may involve surgery to correct a structural problem. Talk with your healthcare provider to find out more about treatment options for your baby's condition.

Prevention

While many congenital conditions can’t be prevented, there are steps you can take to help reduce the risk. They include:

• Getting the daily recommended amount of vitamins and minerals before and during pregnancy, especially folic acid, which can help prevent birth defects of the brain and spine. 
• Making sure you are up-to-date on vaccinations. This can help prevent some infections, like rubella, that can cause a congenital condition.
• Avoiding unnecessary medicine that can cause birth defects. Talk with your healthcare provider about any medications you’re taking to make sure that they’re safe to take while pregnant.
• Avoiding harmful substances like tobacco and alcohol during pregnancy.
• Avoiding travel to regions experiencing outbreaks of infections, such as the Zika virus. 

A Word From Verywell

If you are an expectant parent, talk with your healthcare provider about the risk for congenital conditions. They can help you understand screening and treatment options and provide guidance for future care.