We owe to Professor John Dobbing of Manchester, England the fundamental notions that each fetal organ system has its own time course of development and that there are specific, preprogrammed growth spurts - when there is a lot of metabolic activity and when that organ is especially vulnerable to injury. Many of Professor Dobbings elegant studies of the 1960's and 1970's concerned the effects of fetal malnutrition in later pregnancy on brain growth and function.
We pay a lot of attention to the sequences of development, especially the brain, where a very complex sequence of events has to happen exactly on schedule. The earlier in development a problem occurs, the more serious the consequences are likely to be - and by the same token, the earlier in pregnancy a problem is seen, the poorer the outcome. One of common features of chromosome problems is that cell division rates are slowed and developmental sequences happen later than normal. Ultrasonic findings appear and disappear, depending on the organ system and the time the exam is done. Interpretation requires developmental standards that change throughout pregnancy. |
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We have been using the term "syndrome" without defining it. This image is of turned in or "clubbed" foot - a single finding. A syndrome occurs when there is a regular association between abnormalities in different parts of the body.
Our diagnostic task is to distinguish a problem that is limited to one body part, which might be fixable, from a syndrome - where there are multiple findings and a much lower chance that it can be repaired. An amnio is essential whenever abnormalities are found in order to identify or exclude chromosomal "syndromes". With some non-chromosomal syndrome patterns, DNA testing may lead to an exact diagnosis. There is now a large library of recognized syndromes and of specific genetic markers.
