Prenatal Testing and Diagnosis
Prenatal, or intrauterine, diagnosis is a process that can identify some birth defects and genetic disorders in your child before birth.
Cleveland Clinic's Center for Personalized Genetic Healthcare uses several different testing and evaluation techniques to perform prenatal diagnosis. Depending on your age, family health history and other risk factors, you may undergo a blood draw, an ultrasound examination of your pregnancy, or more invasive forms of testing such as chorionic villus sampling or amniocentesis.
Center for Personalized Genetic Healthcare
9500 Euclid Avenue
Cleveland, OH 44195
Appointments and Genetic Counselors
Phone: 216.445.5686 or 800.998.4785 (toll-free)
Genetic Problems Detectable Before Birth
More than 300 disorders can be detected in unborn infants. Some of the birth defects and genetic disorders for which Medical Genetics provides testing include:
- Down's syndrome (Trisomy 21)
- Cystic fibrosis
- Sickle cell disease
- Tay-Sachs disease
- Fragile X syndrome (a leading cause of mental retardation)
- Spina bifida
- Heart defects
These disorders can have different forms of inheritance, and a genetic counselor may be able to give you a better idea of the chance that your baby will be affected. The first step in the process is to obtain a detailed family history to determine the conditions for which your baby is at risk. Then, information from blood testing and/or ultrasound can be used to provide an assessment of risk, and you may have to make a decision regarding a more invasive procedure for diagnosis. For example, a baby's sex can be determined before birth with ultrasound. This is important in assessing the risk for certain diseases such as muscular dystrophy or hemophilia, which are typically passed from unaffected mothers (carriers) to their sons. For a mother who is known to be a carrier for one of these conditions, there is a 50 percent chance that male offspring will be affected by the disorder.
Not all disorders present at birth can be detected through the tests that are currently available, and some babies who have normal test results are born with birth defects or genetic disorders. A normal ultrasound, maternal blood test, amniocentesis or chorionic villus sample does not guarantee that a baby will not have a problem, but normal test results usually indicate that chances for having a baby without genetic disorders are high.
Reasons For Having Prenatal Testing
The decision to undergo prenatal testing and diagnosis is a personal one. Your doctor can make recommendations, but you must make the decision. Prenatal testing can lead to early detection of certain birth defects or other problems that may require special care. This testing offers parents the opportunity to learn about these conditions and make decisions and plans long before the baby is delivered. Prenatal testing helps parents and doctors work together for the best management of a pregnancy known to be at risk.
Who Should Have Prenatal Testing
Your obstetrician may recommend prenatal testing and diagnosis if you have a higher-than-normal risk of giving birth to a baby with a birth defect or genetic disorder. Women who meet any of the follow criteria have an increased risk and should consider prenatal testing:
- Maternal age of 35 or greater at the time of delivery. The risk of chromosomal abnormalities increases significantly after age 35.
- A previous child with a chromosomal abnormality, birth defect or other inherited condition.
- Family history or an inherited disorder.
- Those who are carriers of X-linked diseases such as hemophilia or muscular dystrophy.
- Those who are carriers, or whose partners are carriers, of a known genetic disorder.
- Belonging to a certain ethnic group or race among which certain inherited disorders are prevalent (e.g., Ashkenazi Jew, French Canadian or Cajun ancestry)
- Abnormal findings on a fetal ultrasound.
The prenatal diagnosis process begins with a meeting with one of our genetic counselors. Your genetic counselor is the person who will guide you through the entire process, explain the various tests available and the risks associated with each, interpret the results and discuss your options at each step. At your first meeting, the counselor will ask you about your family's health history, as well as your personal medical history and that of the baby's father. You should feel comfortable in raising any questions or concerns that you might have with your counselor.