Advances in medical technology and a better understanding of the common genetic conditions found in infants has led to a massive improvement in the accuracy with which certain disorders can be detected at an early stage of pregnancy. One of the most notable conditions that doctors look out for is Down Syndrome.
A calculation taking into account the mother’s age, blood tests at appropriate times, and ultrasound observations can predict with a high degree of accuracy the likelihood that a fetus will have Down Syndrome. The ultrasound in particular has been found to be extremely important in getting these calculations right.
A number of markers for the disease have been identified. These markers are classified as high level markers, mid-level markers and low-level markers (soft markers). As the name suggests, the highest level markers have the strongest relationship with the development of the syndrome.
High Level Markers
These markers, also called the key markers, are the most important ones and so the radiologist looks for these first while conducting the ultrasound.
A thickening of posterior nuchal fold (the distance between the bone on the back of the head and the overlying skin), a normal arrangement of the heart valves and a nasal bone that is not undergoing the normal rate of ossification are considered as high level markers for detecting Down Syndrome.
While it is normal and understandable that loved ones get worried if these markers are detected, it is important to remember that these are only risk predictors. Yes, the risk does go up significantly but just having these findings does not mean that the child has Down Syndrome.
Mid Level Markers
The length of the humerus (upper arm bone) actually measured in the ultrasound divided by the expected length of the humerus is a medium level marker. This ratio, if altered, increases the likelihood of the child developing Down’s syndrome.
Low Level Markers
A measurement of the length of the femur (bone of the leg) and then compared against the expected measurement is a soft marker for Down’s syndrome. Another common soft marker is the presence of a bright colored spot on the heart of the baby. This is more often than not a reflection of a highly calcified area in the developing muscles. An increase in the fluid of the kidneys of the child is also something that the doctors see as a soft marker.
If the doctor has detected one or more of the markers mentioned above then it is likely that further tests and scans will be advised. It is highly recommended that an amniocentesis be carried out if the risk prediction for Down’s syndrome has been found to be on the higher side. Coupled with the presence/absence of ultrasound markers, it can help the detection accuracy to go up to 90%. While the white spots are most often harmless, doctors do advise getting a fetal echocardiogram done as well.
Some parents decide not to get any more tests done or investigations done for fear getting stressed out, however they should know that technology and medical advancements exist to give them the best possible information. How they choose to process that is of course up to them.
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