Prequel® Prenatal Screen

The list below shows what the Prequel Prenatal Screen looks for. Each link will provide greater information on the condition listed. Click the links below to learn more.

Microdeletions and predicted sex chromosome screening are optional.


A trisomy occurs when the cells of the body contain an extra chromosome. This can lead to health issues including birth defects and intellectual disability.

Sex Chromosomes

The sex chromosomes determine whether the baby will be male (XY) or female (XX). Sometimes there may be too many or too few sex chromosomes, resulting in potential health issues.

While looking at the sex chromosomes, we can report the sex of the baby.


A microdeletion occurs when a tiny piece of a chromosome is missing, or deleted. This deletion can result in birth defects or intellectual disability.

Expanded Aneuploidies

Aneuploidies, or having too many or too few chromosomes, can also occur in other chromosomes (beyond 13, 18, 21, and sex chromosomes). This can lead to health issues or indicate an issue with the placenta.