Pregnancy and Congenital Abnormalities

A congenital abnormality or genetic disorder is a health condition that a baby is born with. It can be caused by a chromosomal, hereditary, or environmental issue. However, in some cases the cause of a genetic disorder is not known.

According to the U.S. Centers for Disease Control and Prevention (CDC), approximately 3% of babies are born with congenital abnormalities. Here is an overview of some of the genetic disorders that often worry parents-to-be, along with the causes, risk factors, and prenatal tests that screen for and diagnose genetic problems.

Risk Factors

Babies with congenital issues are often born to parents who do not have any risk factors. However, the following risk factors increase the chances of having a child with a genetic disorder:

Chromosomal Disorders

Chromosomal disorders are caused by an extra or missing chromosome. Sometimes an incorrect number of chromosomes is incompatible with life, and these pregnancies often end in miscarriage. However, some chromosomal conditions can be managed and those affected can enjoy fulfilling lives.

  • Down Syndrome: Down syndrome is the most common chromosomal abnormality, occurring in approximately one in every 700 U.S. births. The chances go up with maternal age, however. There are many support services available to families with a child born with Down syndrome.
  • Klinefelter Syndrome: This disorder results in males receiving an additional X chromosome. It shows up in approximately one in 500 to 1,000 births, although researchers believe that up to 75% of males are never diagnosed. Boys with Klinefelter syndrome produce less testosterone, are often tall, and may have learning disabilities. 
  • Patau Syndrome (Trisomy 18) and Edward’s Syndrome (Trisomy 13): Trisomy 18 and Trisomy 13 are less frequent than Down syndrome. They are also more severe, causing problems with learning ability and affecting almost every organ in the body. Infants born with either syndrome often do not survive their first year. 
  • Turner syndrome: A rare disorder only seen in females, Turner syndrome impacts one in 2,500 babies. Instead of getting two sex chromosomes, affected babies have only X chromosome. Turner syndrome affects height and fertility but not intelligence in most cases. With monitoring and treatment, women with Turner syndrome can lead healthy lives.

Hereditary Disorders 

Hereditary disorders are passed down from parents to their children. Most of the time, hereditary conditions are recessive, which means that two genes for that disorder (one from each parent) are needed for it to show up in the baby.

Certain ethnic groups are more likely to carry genes for specific genetic disorders. When parents are from the same ancestral background, the chances of having a child with certain genetic conditions goes up.

Even though the disorders below are more common among specific groups, they are still rare overall.

  • Beta Thalassemia is a genetic blood disorder found more commonly in people from the Mediterranean region. This condition is fairly common and affects how the body makes red blood cells, leading to anemia.
  • Cystic Fibrosis (CF) is a rare genetic disorder that is more common among people of European ancestry. Cystic fibrosis affects the lungs and other organ systems. Most patients have a lifespan of 30 to 40 years, although medical treatment advances have improved outcomes in recent years.
  • Sickle-Cell Anemia is the most common hereditary disorder in people of African descent. Sickle-cell disease affects red blood cells and occurs in approximately 1 in 70,000 Americans. However, the rate is 1 in 365 among African Americans.
  • Tay-Sachs Disease is typically found in people with certain ancestries, such as Eastern European Jews. About one in 30 American Jews carries one copy of the Tay-Sachs gene. Tay-Sachs causes progressive damage to the nerves in the brain and spinal cord.

Environmental Risks

A teratogen is something that affects the growth and development of a fetus during pregnancy. Exposure to a teratogen in pregnancy can lead to a congenital abnormality.

Substances such as alcohol, drugs, and certain medications, as well as infections like chickenpox, rubella, syphilis, or toxoplasmosis can all affect a baby’s development. The development of a congenital abnormality depends on factors such as:

  • How long the exposure lasts
  • How much of the toxin you (and your baby) are exposed to
  • The stage of pregnancy you’re in (the first trimester is usually the most vulnerable)

Exposure to toxins from the environment can affect every system of your baby’s body, including the head, facial features, brain function, nervous system, heart, ears, eyes, and bones.

Detecting Abnormalities

A variety of screening tests can be done while you're pregnant to check for congenital abnormalities. If you are over the age of 35 or have other risk factors, your doctor may also recommend additional testing.

Some of the screening tests for genetic disorders include:

Genetic Counseling

A genetic counselor is a trained medical professional who gives you information about your risk of having a child with a congenital disorder. They can provide you with preconception counseling or they can counsel you during your pregnancy. 

Genetic counselors take information about your family history, health, and medical history. While you’re pregnant, they gather information from screening tests and follow your baby’s growth.

They can detect any genetic problems and provide you with information on a specific disorder, its course, and management.

You do not need a reason to seek genetic counseling before becoming pregnant. However, the CDC advises that genetic counselors can be particularly helpful in the following cases: 

  • Abnormal results from a prenatal screening test or ultrasound
  • You and your partner share the same ancestral background
  • You are a known carrier of a chromosomal or genetic disorder
  • You are 35 years or older
  • You had a stillbirth or a newborn who passed away
  • You have a family history of chromosomal abnormalities
  • You have been exposed to an illness, infection, or environmental toxin that could affect your baby
  • You have had recurrent miscarriages

What to Do

Learning that the child you’re carrying has a congenital abnormality can be devastating. Depending on the disorder, it may mean only minor health concerns for the child, or it could be something that will have a lifelong effect on your family.

Although you may face some difficult decisions, there are also steps you can take to make the process easier.

  • Talk to your doctor and a genetic counselor. Ask questions and get all the information you can about the diagnosis, including what you need to know about management and treatment. Go over your options and take the time to think about and process all the information. 
  • Sorrow and anger are normal. Whether you have to say goodbye to your child or you’re grieving the loss of the child you expected to have, take the time to work through your emotions. Talk openly about your feelings with your partner, family, friends, or mental health professional.
  • If you will be experiencing the loss of a child, counseling can help you through the process of grieving. If you are having a child who will have health concerns, seeking counseling before you deliver will help you prepare for, accept, and bond with your special needs child after they are born.
  • Talk to your partner about how you feel, but also make sure to let your partner express their feelings to you. Lean on and support each other. 
  • Learn all you can about your child’s condition. The more you know, the more you can do to prepare for a special needs child, arrange services, and help your child get the best start in life.
  • Join a support group and seek out friends and family who can give you the support you need as you come to terms with your child’s condition. There are resources you can connect and work with to get your child the services and support they need. 
  • Find out what services are available to you and your child before they arrive. After you have your baby, speak with a social worker and case manager in the hospital, as they can provide additional referrals. Early intervention can help you set up what your family needs.

A Word From Verywell

It’s normal to worry about the health of your baby while you are pregnant—especially if you are an older mom, you have a known genetic risk factor, or you have a family member with a genetic health condition. It can also be stressful to go through routine prenatal screenings and have to wait for results.

Keep in mind that 97% of babies are born healthy. If your baby is in the 3% born with a congenital issue, there are treatment options and services available.

Together with your baby’s doctors, you can make the right decisions for your family, manage your baby’s health needs, and plan the best possible life for your child.

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12 Sources
Verywell Family 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. Centers for Disease Control and Prevention. What are birth defects? December 4, 2020.

  2. Harris BS, Bishop KC, Kemeny HR, Walker JS, Rhee E, Kuller JA. Risk factors for birth defects. Obstet Gynecol Surv. 2017;72(2):123-135. doi:10.1097/OGX.0000000000000405

  3. Centers for Disease Control and Prevention. Facts about down syndrome. April 6, 2021.

  4. U.S. National Library of Medicine. Klinefelter syndrome. Updated September 8, 2020.

  5. Children's Wisconsin. Genetic disorders.

  6. Sheridan E, Wright J, Small N, Corry PC, Oddie S, Whibley C, Petherick ES, Malik T, Pawson N, McKinney PA, Parslow RC. Risk factors for congenital anomaly in a multiethnic birth cohort: an analysis of the Born in Bradford study. The Lancet. 2013 Oct 19;382(9901):1350-9. doi:10.1016/S0140-6736(13)61132-0

  7. U.S. National Library of Medicine. Beta thalassemia. September 1, 2015.

  8. National Heart, Lung, and Blood Institute. Sickle cell disease. Updated September 1, 2020.

  9. Cleveland Clinic. Birth defects. February 4, 2021.

  10. American College of Obstetricians and Gynecologists. Prenatal genetic screening tests. Updated October 2020.

  11. Centers for Disease Control and Prevention. Genetic counseling and testing. March 23, 2020

  12. Nemours KidsHealth. When your baby has a birth defect. October 2016.

Additional Reading
  • Bienstock JL, Fox HE, Wallach EE, Johnson CT, Hallock JL. Johns Hopkins Manual of Gynecology and Obstetrics. Lippincott Williams & Wilkins; 2015 Mar 23.
  • Milunsky A, Milunsky JM. Genetic disorders and the fetus: diagnosis, prevention, and treatment. John Wiley & Sons; 2015 Nov 9.