Home Birth Defects Explained: Types, Causes, Diagnosis, and Support for Families

Birth Defects Explained: Types, Causes, Diagnosis, and Support for Families

In the United States, a baby is born with a major birth defect every 4 1/2 minutes. If your child has recently been diagnosed or you’re searching for reliable information and emotional support, you’re not alone. This guide will help you understand what birth defects are, what causes them, how they’re diagnosed, and what support systems are available.

Join our National Birth Defect Registry to connect with other families, access trusted resources, and contribute to research that improves care and outcomes for all children.

 

Birth Defects Summary: Key Facts

  • What is a birth defect? A birth defect (congenital disorder or anomaly) is a structural or functional problem present at birth, affecting how the body looks, works, or both.
  • How common are birth defects? In the United States, a baby is born with a major birth defect every 4 l/2 minutes.
  • What causes birth defects? The majority of birth defects (80%) are caused by an interaction of genetic predisposition and some factor in the maternal, paternal or preconceptual environment.About 20% of congenital defects are inherited through dominant or recessive genes.
  • Are they preventable? Not all birth defects can be prevented, but healthy habits—like taking folic acid, avoiding alcohol, and managing medical conditions—can reduce risk. Our Healthy Baby Resource provides up-to-date information on how to have a healthier baby.
  • How are they diagnosed? Birth defects are diagnosed through prenatal screening (ultrasounds and blood tests), specialized diagnostic tests, and newborn screening after birth.
  • Why early detection matters: Detecting a defect early—before or soon after birth—can lead to timely interventions and improved health and developmental outcomes.

Birth Defects Research for Children is the only organization in the world collecting data on both maternal and paternal exposures, and on functional as well as structural birth defects, to better understand their causes. Our research has already led to major breakthroughs—from identifying dangerous environmental toxins to helping remove harmful drugs from the market.

 

What Are Birth Defects?

Birth defects are problems that develop while a baby is growing during pregnancy. They can be structural or functional in nature. Structural birth defects affect the physical parts of the body like the heart, spine, or limbs, whereas functional defects impact how the body works, such as how it processes food or senses the world. Some birth defects are visible right away, like a cleft lip, while others, like certain heart defects, might only be detected through medical testing or become noticeable later in life.

Examples of Birth Defects

A child born with a congenital heart defect may have a hole in the heart or a problem with the heart’s valves or walls. Another child might have a cleft lip or palate, where the upper lip or roof of the mouth does not fully form. Spina bifida is a birth defect where the spinal column does not close completely. Down syndrome results from an extra chromosome and can affect both physical development and learning abilities. Club foot is a condition where a baby’s foot is twisted out of shape or position. Learn more about specific types of birth defects in our detailed fact sheets.

How Common Are Birth Defects?

Birth defects are more common than most people realize. In the United States, about one out of every 33 babies is born with a birth defect each year, making these conditions one of the leading causes of infant death and childhood disability. Globally, millions of babies are born with congenital anomalies annually, with some regions experiencing higher rates due to differences in access to healthcare, nutrition, and environmental factors. While medical advances have led to improvements in early detection and treatment, birth defects still account for nearly one in five infant deaths in the U.S. Even for children who survive, many require ongoing medical care, surgeries, or special therapies. Explore more birth defect statistics and trends on our data and research page.

Types of Birth Defects

 

Structural Defects

Structural birth defects are physical abnormalities that can be seen or detected, often with the help of medical imaging. For example, congenital heart defects are among the most common and can involve holes in the heart, blocked blood vessels, or problems with heart valves. Cleft lip and cleft palate occur when the tissues that form the lip or mouth do not join completely before birth, leading to an opening in the lip or the roof of the mouth. Spina bifida is a condition where the baby’s spinal column does not close completely, sometimes causing nerve damage and physical disability. Neural tube defects also include anencephaly, where parts of the brain or skull do not develop. Club foot is when a baby’s foot is turned inward or downward, and without treatment, it can affect walking.

Functional/Developmental Defects

Functional or developmental birth defects affect how a body system works, rather than how it looks. For instance, metabolic disorders such as phenylketonuria (PKU) prevent the body from breaking down certain nutrients, leading to a build-up of harmful substances if not managed. Some children are born with sensory problems, such as hearing loss or blindness, which can impact their development and learning. Neurodevelopmental disorders may include Autism Spectrum Disorders, learning disabilities, developmental delays, and attention disorders which may affect how a child moves, learns, or communicates. Endocrine disorders can affect immunity and lead  to childhood cancers, autoimmune conditions and endocrine problems like diabetes. Many of these issues may not be obvious at birth but become apparent as a child grows.

Most Common Types

The most common structural birth defects include congenital heart defects, which are seen in about 1 in every 110 births. Down syndrome, a genetic condition caused by an extra chromosome, affects around 1 in every 700 babies in the U.S. Cleft lip and/or palate affects about 1 in 940 babies. Spina bifida and other neural tube defects occur in about 1 to 2 in every 10,000 births. Club foot is seen in about 1 in every 250 babies born. While some of these can be diagnosed before birth, others may only be identified in the first days or weeks of life. Other common birth defects include hypospadias, which affects about 1 in every 150 male births, and polydactyly, where a child is born with extra fingers or toes and occurs in approximately 1 in 500 to 1,000 live births. Gastroschisis, a condition in which a baby’s intestines develop outside of the body, is seen in about 1 in 2,229 births. Microtia and anotia, which involve an underdeveloped or missing ear, are found in around 1 in 3,800 live births. Another serious defect, congenital diaphragmatic hernia, where a hole in the diaphragm allows abdominal organs to move into the chest, occurs in roughly 1 in 3,836 births.

More on the most common birth defects:

 

Rare Defects

While certain birth defects are more well-known, thousands of rare congenital disorders exist, such as craniofacial anomalies, limb reduction defects, and rare metabolic conditions. These rare conditions may affect only a handful of families in a region each year, but collectively, they represent a significant portion of pediatric healthcare needs. For a complete list of rare birth defects, see our glossary or rare conditions page.

More on the rarest birth defects:

 

National Birth Defect Registry

To help families find information easily, we offer a searchable directory and glossary of birth defects, including links to detailed articles about each condition, possible causes, signs, and support resources.

 

Causes & Risk Factors

 

Genetic Factors

Some birth defects are caused by changes or mutations in a baby’s genes or chromosomes. These genetic factors can be inherited from one or both parents, or they can happen spontaneously for unknown reasons. For example, Down syndrome results from an extra chromosome 21, while cystic fibrosis and sickle cell disease are inherited conditions passed down in families. If a family has a history of certain birth defects, the chances may be higher in future pregnancies.

Environmental and Lifestyle Factors

The environment in which a baby develops can also play a big role in the risk of birth defects. If a mother is exposed to certain substances—such as alcohol, tobacco, illicit drugs, or harmful chemicals—while pregnant, it can raise the risk of problems with the baby’s growth or development. Nutritional factors matter, too; for example, not getting enough folic acid during pregnancy increases the risk of neural tube defects. Certain infections during pregnancy, like Zika virus or rubella, are known to cause congenital disorders. Exposure to environmental pollutants, pesticides, or radiation can also increase risk.

Medical Conditions & Medications

Some health conditions in the mother, such as diabetes or obesity, can make birth defects more likely, especially if they are not well controlled before or during pregnancy. Certain prescription medications—such as those used for epilepsy, mood disorders, or severe acne—have been linked to higher rates of birth defects if taken during pregnancy. Over-the-counter medications can also be a risk factor for some birth defects. Always talk with your healthcare provider before starting or stopping any medication if you are pregnant or planning to become pregnant.

Age, Infections, and Other Risks

Maternal age can also influence risk. Women who become pregnant after age 35 have a higher chance of having a child with some chromosomal conditions, like Down syndrome, but younger women are not immune to risk. Infections such as cytomegalovirus (CMV), toxoplasmosis, or chickenpox during pregnancy can lead to birth defects, especially if they occur in the first trimester.

Risk Factors Checklist

If you are pregnant or planning to become pregnant, consider these risk factors:

  • Do you or your partner have a family history of birth defects or genetic conditions?
  • Have you been exposed to tobacco, alcohol, drugs, or environmental toxins during pregnancy?
  • Are you managing any chronic health issues, such as diabetes, obesity, or epilepsy?
  • Are you taking any prescription or over-the-counter medications?
  • Have you experienced any infections while pregnant?
  • Do you or the father work in a job that may involve exposure to toxins (i.e. nail salon or farming)?
  • Are there increases in birth defects reported in your community?
  • Are you taking prenatal vitamins, especially folic acid, as recommended by your doctor?
  • Are you over age 35 or under age 18?

Talk with your healthcare provider to review your personal risk and steps to help reduce it.

Myths vs. Facts

While every birth defect has a cause, this cannot always be determined or prevented.  But, by participating in the National Birth Defect Registry you can help to identify unknown causes and prevent future birth defects.

Can Birth Defects Be Prevented?

Not all birth defects are preventable, but many steps can help reduce risk and promote a healthy pregnancy. Taking a daily prenatal vitamin with folic acid before and during early pregnancy may be one of the most effective ways to prevent serious neural tube defects like spina bifida. Women are also encouraged to avoid alcohol, tobacco, and recreational drugs, as these substances can cause severe problems for a developing baby. Managing chronic conditions like diabetes, maintaining a healthy weight, and attending regular prenatal visits are all important in lowering risk. Talk to your doctor about the risks of any prescription or over-the-counter medication. Practicing good hand hygiene, avoiding and protecting yourself from mosquito-borne illnesses also contribute to a healthier pregnancy. While not every birth defect can be avoided, these healthy choices make a real difference for many families.

For more tips and practical guidance, visit our Healthy Baby Resource.

Detection & Diagnosis

 

During Pregnancy

Modern prenatal care offers several ways to detect birth defects before a baby is born. Routine ultrasounds can sometimes spot structural issues with the heart, brain, spine, or other organs. Blood tests, such as the quad screen or cell-free DNA tests, can identify certain chromosomal conditions like Down syndrome or spina bifida. For high-risk pregnancies or when screening tests show a possible problem, doctors may recommend diagnostic procedures like amniocentesis or chorionic villus sampling (CVS), which analyze fetal cells for genetic or chromosomal abnormalities. Non-invasive prenatal testing (NIPT) is increasingly used for early screening, especially in women over 35 or those with a family history of birth defects.

After Birth

If a birth defect is not identified during pregnancy, newborn screening programs can help detect issues soon after birth. Most babies in the U.S. undergo a blood test within the first days of life to screen for dozens of rare metabolic, genetic, or endocrine disorders. Newborns also typically receive a hearing test and a screening for critical congenital heart disease using pulse oximetry, a painless measurement of blood oxygen. Some conditions may become apparent through physical exams or as the baby grows and develops.

Importance of Early Diagnosis

The sooner a birth defect is detected, the more options families have to plan care, start treatment, and access resources. Early intervention can make a significant difference in health, development, and quality of life.

 

How to Cope with Worry During Pregnancy

If you find yourself feeling anxious, try to focus on proactive steps you can take for peace of mind:

  • Attend all recommended prenatal appointments for early screening and reassurance.
  • Take prenatal vitamins with folic acid and follow your doctor’s advice about healthy habits.
  • Avoid alcohol, tobacco, and risky substances as much as possible.
  • Stay informed with reliable resources.

If worries feel overwhelming, remember that support is available. Visit our Parent Support Center to find counseling resources, support groups, and practical coping strategies for expectant parents.

Treatment & Living With Birth Defects

 

Medical Teams Involved

Caring for a child with a birth defect often involves a team of specialists working together. Pediatricians coordinate care and monitor the child’s health and development. Pediatric surgeons may be needed for procedures to repair heart defects, cleft lip or palate, or other physical problems. Genetic counselors help families understand genetic conditions, their causes, and what to expect. Therapists—such as physical, occupational, or speech therapists—support children’s development, learning, and daily functioning. Social workers help connect families to resources, emotional support, and financial aid.

Home/School Life

Many children with birth defects live active, fulfilling lives with the right support at home and in school. Parents may need to learn new ways to care for their child’s needs, administer medications, or use medical equipment. Schools may provide accommodations, such as extra time for tasks, adaptive devices, or individualized education plans (IEPs), to help children learn and grow alongside their peers. Parents can find daily tips, guides, and checklists for home care on our family resources page.

Real Parent/Patient Stories

Hearing from other parents and children facing similar challenges can offer hope and practical advice. Many families share their experiences of navigating diagnosis, finding the right care, and celebrating milestones big and small. If you would like to share experiences with other families, join our Parent Matching Project.

Emotional & Practical Support for Families

Discovering that your child has a birth defect can be overwhelming, stressful, and sometimes isolating. Emotional and practical support are just as important as medical care. Support groups—both local and online—offer a safe place to connect with others, ask questions, and share experiences. Mental health resources are available for parents, siblings, and caregivers, including counseling, therapy, and stress management tools. Community events, peer mentoring, and online forums help families feel less alone and more empowered.

Join Our Registry

Unlike any other organization in the world, our National Birth Defects Registry collects detailed data on both maternal and paternal exposures, and covers both structural and functional birth defects. While around 20% of birth defects are entirely genetic, the remaining 80% result from a mix of genetic predisposition and environmental triggers—like viruses, medications, or toxic chemicals. By joining our registry, you’re not just connecting with support and resources. You’re contributing to groundbreaking research that has already:

  • Identified the causes of gastroschisis
  • Linked a cluster of cleft palate cases to toxins leaking into the public water supply from a landfill
  • Helped remove a harmful drug from global circulation
  • Exposed patterns of rare defects in the children of Gulf War and Vietnam veterans
  • Pioneered research on male-mediated birth defects

Sign up now—it’s free, secure, and can help you and others facing similar challenges.

Frequently Asked Questions

 

 

What are the most common birth defects?

The most common birth defects are congenital heart defects, cleft lip and/or palate, Down syndrome, spina bifida, and clubfoot. These conditions account for a large percentage of diagnosed birth defects each year.

What causes birth defects while pregnant?

Birth defects can be caused by genetic changes, environmental exposures, or a combination of both during pregnancy. Examples include inherited genetic factors, infections, certain medications, and exposure to harmful substances.

Can birth defects be prevented?

Not all birth defects can be prevented, but you can lower your risk by making healthy choices and getting prenatal care. Taking folic acid, avoiding alcohol and tobacco, and managing health conditions all help.

When are birth defects detected?

Birth defects can be detected before birth through screening and ultrasound, or after birth with newborn screening and exams. Early detection often leads to better outcomes.

Are birth defects hereditary?

Some birth defects are hereditary, but most are not. While family history can increase risk, most cases happen with no prior family link.

How are birth defects diagnosed?

Birth defects are diagnosed with prenatal screening (ultrasound and blood tests), diagnostic procedures, and newborn screening after birth. Physical exams and follow-up tests can confirm a diagnosis.

How severe can birth defects be?

Birth defects can range from mild to life-threatening. Some have little impact on health or development, while others may require surgery or long-term care.

What are the four main causes of birth defects?

The four main causes of birth defects are genetic factors, environmental exposures, maternal health conditions, and unknown causes. Sometimes, it’s a mix of more than one factor.

What support is available for parents?

Parents can get support through counseling, support groups, financial aid, birth defect registries, and national parent matching. Connecting with others helps you feel less alone.

What is a birth defects registry?

The National Birth Defect Registry is a secure database for families to contribute information to help identify causes of birth defects. Parents who participate in the registry can also be matched with other families who have children with the same conditions.

Join our National Birth Defect Registry – Connect, Learn, and Help Advance Birth Defects Research and Support

If you want to participate in helping to identify the unknown causes of birth defects, the Birth Defects Registry is your first step toward connection, empowerment, and hope. Sign up now—it’s free, private, and can make a real difference for your family and others.

Comments are closed.