Congenital Conditions and Diseases

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Congenital conditions and diseases are present at or before the birth of a baby. 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.

Getty Down Syndrome
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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.


During conception, a child gets 46 chromosomes total – 23 from the mother and 23 from the father. 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.


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

Maternal infections can cause serious congenital conditions in an unborn baby, especially during the first nine weeks of pregnancy. Those infections include toxoplasmosis, cytomegalovirus, chicken pox, and 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 cause birth defects during a mother’s pregnancy. Always check with your healthcare provider to make sure that your medications are safe to take while pregnant.


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 if your baby is at risk for any conditions. For example, if the mom has the gene for cystic fibrosis, the dad may be tested as well since both parents must be carriers for the baby to be at-risk. Tests may also be ordered to determine if the mom 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 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.


While many congenital conditions can’t be prevented, there are steps you can take to help reduce your baby’s 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 your baby’s risk for congenital conditions. They can help you understand screening and treatment options and provide guidance for future care. 

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3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. American Academy of Pediatrics. Congenital Abnormalities. Updated November 19, 2019.

  2. Nemours Foundation. Birth Defects. KidsHealth. Updated September 2017.

  3. World Health Organization. Congenital anomalies. Updated September 7, 2016.