Understanding Birth Defects: Types, Causes, & Risks

A birth defect is a medical condition that occurs while a fetus is developing in the womb.1 Birth defects can cause physical disability, and can be mild or severe.1 Some birth defects affect the organs and how they function, while others affect how a baby develops.1

There are several possible conditions that can lead to the development of birth defects, and certain risk factors may increase the risk of a fetus developing one.2

If you are family planning, it can be important for you to learn about birth defects, including types, possible causes, and your personal risk factors. You can also learn howmaternal-fetal medicine specialists diagnose these conditions, and how they are treated.

A few words about the term birth defect

“Birth defect” is a medical term used to describe structural or developmental problems that start during fetal development. However, not everyone is comfortable with this term.3
It’s important to use the term “birth defect” simply as a description—as something that someone has. No person is defective. Here are some alternative terms:

• Congenital conditions
• Congenital anomalies/abnormalities
• Congenital malformations
• Physical malformations

How common are birth defects?

Birth defects are not uncommon. One in every 33 babies born each year in the United States is affected by a birth defect.2 This is equal to around 120,000 babies each year.2
Birth defects are the leading cause of death for infants in the first year of life.4 Approximately one in five infant deaths are caused by problems related to a congenital condition.4

Types of birth defects

There are thousands of congenital conditions. The most common birth defects typically fall into one of two main categories: structural or functional/developmental.5

Some conditions —like spina bifida—can fall into both the structural and functional categories, because the condition affects fetal development in both ways.6

Structural birth defects occur when a body part is missing or malformed. Some of the most common structural birth defects include:5

• Cleft lip or palate (a split or opening in the lip or roof of the mouth)
• Atypical limbs, such as clubfoot (when one or both feet are turned inward)
• Heart defects
• Spina bifida (irregular spine development)

Functional or developmental birth defects affect how a body part or body system works. Some cause problems with intellectual development. Examples include:5

• Nervous system or brain problems, which can lead to intellectual and developmental disabilities, speech or language problems, behavioral disorders, seizures, or difficulty with movement. Spina bifida and Down syndrome are two examples.
• Sensory problems, such as deafness or blindness stemming from problems with the development of the auditory or visual systems.
• Metabolic disorders, which can cause problems with waste elimination and other chemical processes in the body. Examples of metabolic congenital disorders include phenylketonuria (PKU) and hypothyroidism.
• Degenerative disorders, such as muscular dystrophy, where progressive deterioration of muscle tissue occurs due to genetic mutations affecting muscle proteins.
  While some children have noticeable problems related to a birth defect, others show no visible signs. In these cases, a problem may go unnoticed for months or even years.1

What causes birth defects?

In most cases, the cause of a birth defect is unknown.2

Birth defects can occur during any stage of pregnancy. Birth defects are often caused by a complex mix of factors,2 which can include one or more of the following:7

• Genetic problems: Genes can change or mutate during pregnancy, which can result in them not working properly. Additionally, a gene or part of the gene may be missing.
• Chromosomal problems: A chromosome or part of a chromosome may be missing, or there may be an extra chromosome.
• Having certain medical conditions: Such as having obesity, or having uncontrolled diabetes before pregnancy.
• Infections: Certain infections during pregnancy, such as Zika virus, toxoplasmosis, or cytomegalovirus can affect a developing fetus.
• Exposure to chemicals, medications, and other substances during pregnancy: Taking certain medications, such as isotretinoin (used to treat acne); smoking; drinking alcohol; using illicit drugs; and exposure to toxic chemicals can all be linked to birth defects.

What are the risk factors for birth defects?

Certain conditions can put parents at greater risk of having a child with a birth defect.1 For example, a family history of certain genetic conditions from either parent can increase the risk of congenital disorders. Additionally, the physical health of the parent giving birth can contribute to their child developing birth defects. These risk factors that can impact pregnancy include:1,8

• Diabetes
• Obesity
• Substance use disorders
• Maternal age (being over 35 years old)
• Taking certain medications
• Exposure to chemicals or toxic substances
• Having a high fever or body temperature
• Certain infections during pregnancy
   

If you are the birthing parent and have an underlying condition like diabetes or a substance use disorder (SUD), it’s important to discuss this right away with your healthcare provider.

Having one or more of these risks doesn’t mean you’ll have a pregnancy affected by a birth defect. Additionally, women can have a baby born with a birth defect even when they don’t have any of these risks.

Can birth defects be prevented?

While you can’t prevent most birth defects, there are things you can do to stay healthy during pregnancy to help reduce the likelihood of your baby having one.2 For pregnant people, this includes:8,9,10

• Getting prenatal care and seeing your healthcare provider on schedule
• Not smoking or using alcohol, marijuana, or other drugs, or being exposed to second-hand smoke
• Taking a folic acid supplement if you are trying to become pregnant or are pregnant (ask your doctor whether to take folic acid and how much)
• Avoiding medications not prescribed by your doctor (make sure all your healthcare providers know you are pregnant or trying to become pregnant)
• Avoiding toxic chemicals
• Treating fever promptly
• Avoiding saunas and hot tubs, especially in the first trimester of pregnancy
• Avoiding exposure to infectious diseases, such as Zika virus, toxoplasmosis (avoid dirty cat litter and any kind of animal droppings), and CMV (cytomegalovirus)
• Keeping diabetes under control
• Striving to maintain a healthy weight
   

Talk with your healthcare provider about how to keep yourself and your fetus healthy during your pregnancy. This should include a review of your medications and a discussion of alternatives for medications that may not be safe to take during pregnancy.

Prenatal genetic testing can identify certain conditions and provide information about the fetus’s health.11 A genetic counselor can help those with a family history of congenital conditions assess their risk.11

How are birth defects diagnosed?

Birth defects may be diagnosed during pregnancy, in the months after your child is born, or in some cases after signs and symptoms develop.12

Certain screening tests can detect birth defects and genetic conditions at different stages of pregnancy.12

For example, your healthcare provider may order blood tests and conduct ultrasounds in the first trimester to identify fetal heart defects and chromosomal conditions, such as Down syndrome.12

In the second trimester, your provider may order tests to check for structural abnormalities, such as spina bifida.12 If any of these screening tests come back positive, the provider may order additional tests, such as amniocentesis, fetal echocardiogram, or fetal MRI.12

Congenital abnormalities like a cleft lip may not be diagnosed until after your baby is born.12 Other conditions may not be diagnosable until later childhood or even adulthood.12

How are birth defects treated?

Treatment options depend on the type and severity of the congenital condition. Treatments may include medications, assistive devices, or surgery.13

Some conditions can be treated in utero, such as amniotic band syndrome, where fibrous bands from the amniotic sac get tangled around part of the fetus, such as a digit (finger or toe), limb, or even the neck.14 Other congenital conditions, such as a cleft lip, can be corrected shortly after birth.15 Birth defects such as cerebral palsy or spina bifida can be mild or severe. Mild cases may cause little to no disability, while other cases may require lifelong care.16,17

Your doctor will explain which treatments are most appropriate for your child.

OB/GYN Care & Fetal-Maternal Medicine at Crystal Run Healthcare

Every parent wants health and happiness for their child. We know it can be frightening to learn that your child might have a congenital condition. While you can’t prevent most birth defects, there are steps you can take before and during your pregnancy that may help reduce your risk. Our team is here to help you improve your chances of having a healthy baby.

OurOB/GYN providers offer expert prenatal and obstetrical care, working in coordination with ourfetal-maternal medicine team. These specialists treat women at risk for complications during pregnancy and provide diagnostic and therapeutic procedures during pregnancy.

Your family is in good hands with the team at Crystal Run Healthcare. Contact us toschedule an appointment with an experienced provider today.

Sources:

1. MedlinePlus. Birth Defects, Updated 1/26/2024. Birth Defects | MedlinePlus, Accessed 4/1/2024
2. CDC. What Are Birth Defects?, Updated 6/28/2023. What Are Birth Defects? | CDC, Accessed 4/1/2024
3. Eunice Kennedy Shriver National Institute of Child Health and Human Development. Congenital Anomalies, Updated 12/21/2023. Congenital Anomalies | Eunice Kennedy Shriver National Institute of Child Health and Human Development, Accessed 4/1/2024
4. CDC. Data & Statistics on Birth Defects, Updated 6/28/2023. Data & Statistics on Birth Defects | CDC, Accessed 4/1/2024
5. Eunice Kennedy Shriver National Institute of Child Health and Human Development. What Are the Types of Congenital Anomalies?, Updated 12/21/2023. What Are the Types of Congenital Anomalies? | Eunice Kennedy Shriver National Institute of Child Health and Human Development, Accessed 4/1/2024
6. Eunice Kennedy Shriver National Institute of Child Health and Human Development. About Spina Bifida, Updated 1/18/2022. About Spina Bifida | Eunice Kennedy Shriver National Institute of Child Health and Human Development, Accessed 4/1/2024
7. Eunice Kennedy Shriver National Institute of Child Health and Human Development. What Causes Congenital Anomalies?, Updated 12/21/2023. What Causes Congenital Anomalies? | Eunice Kennedy Shriver National Institute of Child Health and Human Development, Accessed 4/1/2024
8. CDC. Commit to Healthy Choices to Help Prevent Birth Defects, Updated 6/28/2023.  Commit to Healthy Choices to Help Prevent Birth Defects | CDC, Accessed 5/10/2024
9. The American College of Obstetricians & Gynecologists (ACOG). Can I Use a Sauna or Hot Tub Early in Pregnancy?, Published 9/2021. Can I Use a Sauna or Hot Tub Early in Pregnancy | ACOG, Accessed 5/10/2024
10. CDC. 10 Tips for Preventing Infections Before and During Pregnancy, Last Reviewed 9/29/2022. 10 Tips for Preventing Infections Before and During Pregnancy | CDC, Accessed 5/10/2024
11. MedlinePlus. Prenatal Genetic Counseling, Updated 1/6/2022. Prenatal Genetic Counseling | MedlinePlus, Accessed 4/1/2024
12. CDC. Diagnosis of Birth Defects, Updated 6/28/2023. Diagnosis of Birth Defects | CDC, Accessed 4/1/2024
13. Eunice Kennedy Shriver National Institute of Child Health and Human Development.  What Are the Treatments for Congenital Anomalies?, Updated 12/21/2023. What Are the Treatments for Congenital Anomalies? | Eunice Kennedy Shriver National Institute of Child Health and Human Development, Accessed 4/1/2024
14. MedlinePlus. Amniotic Band Sequence, Updated 11/9/2021. Amniotic Band Sequence | MedlinePlus, Accessed 4/1/2024
15. CDC. Facts About Cleft Lip and Cleft Palate, Updated 6/28/2023. Facts About Cleft Lip and Cleft Palate | CDC, Accessed 4/1/2024
16. CDC. What Is Cerebral Palsy?, 2/28/2024. What Is Cerebral Palsy? | CDC, Accessed 4/1/2024
17. CDC. What Is Spina Bifida?, Updated 10/4/2023. What Is Spina Bifida? | CDC, Accessed 4/1/2024