For pregnant women over the age of 35, extra monitoring and screening may be recommended to detect for chromosomal abnormalities in their pregnancies.
In order to determine if there are extra or missing chromosomes, there are several testing options.
First, women can do a blood test. The one most recommended is called non-invasive prenatal testing. It is 99% accurate in screening for the most common chromosomal abnormalities.
A diagnostic option is called an amniocentesis. Through an amniocentesis, we can culture your baby’s cells to search for missing or additional chromosomal information. Finally, another test called a microarray looks even more in depth.
These screenings can be valuable, but also confusing at times. Dr. Rachael Overcash, a maternal-fetal medicine specialist at MedStar Washington Hospital Center, has a unique explanation for how these tests search fetal DNA, looking for the missing chromosomes.
“I like to explain the testing options to my patients using the analogy of a set of encyclopedias, with 23 volumes representing the 23 pairs of chromosomes. The amniocentesis examines the set of encyclopedias for missing volumes or entire books. The microarray looks deep into the pages and can find missing or additional sections or paragraphs. And in the future, testing may be so advanced that we will be able to see if a single word or letter is missing.”
Ask your doctor or a maternal-fetal medicine specialist which screening options are best for you and your family.
Our specialists are experts in the care of high-risk pregnancies. For an appointment, call us at
As heard on WTOP Radio:
Rachael Overcash, MD
MedStar Washington Hospital Center