“Looking into our Baby’s Genes: Aneuploidy Screening and Testing” – with Dr. Tamar Goldwaser

Dr. Tamar Goldwaser returns to Healthful Woman for episode two of the Prenatal Genetics mini series. She discusses aneuploidy screening, a test to check for the number of chromosomes present and whether a person has more or fewer than the expected 46 chromosomes. This can indicate a number of genetic conditions, and Dr. Goldwaser discusses the pre-test counseling that she performs with patients to understand why they want to have the tests and what their plans might be in the event of an abnormal result.

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In this episode, Dr. Tamar Goldwaser explains aneuploidy screening. “Aneuploidy” refers to a different number of chromosomes than the expected 46. An aneuploidy result can cause a large number of conditions, the most well-known of which is Down syndrome.  

Dr. Goldwaser explains that aneuploidy screening is conducted to better understand and prepare for chromosomal abnormalities so that patients can know ahead of time if any conditions may be present and whether their baby will be healthy. She says that pre-test counseling is important so that patients can understand what they are looking for and what to expect throughout the process. Dr. Goldwaser notes that “I almost feel bad when I present the options to patients, because it’s overwhelming.”  

First, Dr. Fox and Dr. Goldwaser explain what a normal test result means. They caution that even if aneuploidy testing comes back normal, that doesn’t mean that the baby is guaranteed to be healthy and, in fact, “there’s no such thing as a perfect baby, there’s no such thing as 100% healthy.” Additionally, there are some conditions that can’t be tested for prenatally.  

Drs. Fox and Goldwaser also explain that abnormal aneuploidy screening results don’t always indicate that there is a problem. Screening checks for an increased risk or the likelihood of an abnormality, and typically serve to show who would potentially benefit from a more invasive test. Dr. Fox explains that this is similar to a mammogram, in which an irregular result would mean a patient should have a biopsy, but they don’t necessarily have cancer; the less invasive test serves to prevent every single patient from undergoing a biopsy.  

In addition, more invasive testing, such as an amniocentesis, has what Dr. Goldwaser describes as a “small but real risk of miscarriage,” in addition to being uncomfortable and often frightening for the patient to undergo. This risk is generally less that 1%, but avoiding unnecessary invasive testing is still preferred.  

Drs. Goldwaser and Fox also discuss why patients may choose to have prenatal genetic testing. They explain that it’s often determined by the individual personality of the patient and whether they are comfortable with uncertainty. Some patients may also want to be as prepared as possible and looking for information about whether they will need services in the future, where they should deliver, whether they wish to end a pregnancy, or other factors. Dr. Goldwaser explains the importance of allowing patients the time and space to consider these questions and make their own decisions with guidance from their physician.  

Finally, Dr. Goldwaser explains various types of genetic testing that are available, including nuchal translucency tests, blood testing, micro-array tests, and more. She explains the purpose of each type of test, how they are performed, and what they can detect.