25 - Teratology I Flashcards
Teratology
The study of congenital defects
Annual # of birth defects in live births in US
7% (~200,000)
Number of infant deaths, stillbirths, and spontaneous abortions believed to be due to defects in prenatal development.
> 500,000
Percentage of defects due to spontaneous genetic errors
20-30%
Percentage of defects relatable to the use of certain drugs
6%
Percentage of defects of which the cause remains unknown
60%
How many drugs does the average woman take during her pregnancy?
10 (most without supervision of physician)
How many women are exposed to potential chemical teratogens in their jobs annually in the US?
125,000
What % of abnormalities can be detected at birth?
<50%
What % of early embryos are estimated to die unrecognized?
30%
What % of recognized pregnancies abort spontaneously?
15%
In some cases a birth defect may be detected but a causal link to a specific agent may not be made, why?
because that defect is only expressed under conditions of a genetic predisposition or of certain physiological or pathological states or environmental stresses
What is a major problem with most human teratological studies?
They are confined to the perinatal period and do not adequately evaluate the maturation process.
If children are monitored for about 5 years after birth the total number of defects discovered…
increases 6 times (and some anomalies such as cardiac defects or behavioural problems may not be detected until even later)
Diethylstilbestrol (DES)
Girls exposed to this do not develop vaginal adenocarcinomas until puberty.