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Welcome to the module on reproductive and developmental toxicology.
I'm Alan Hoberman, I'm the Executive Director for global reproductive, developmental,
and juvenile toxicology at Charles River Laboratories, Preclinical Services.
The objectives of today's talk will be:
to describe the importance of reproductive and developmental toxicity testing;
to describe the guidance for testing of reproductive and developmental toxicants;
to provide an overview of reproductive and developmental toxicity endpoints;
and finally to describe the outcomes of this type of testing.
Reproductive and developmental toxicology, why is it important?
Reproductive and developmental toxicology is a specialty area of toxicology.
It looks at the potential adverse effects of a test material, drug, medical device, or chemical.
It looks at what the effects of these are on male and female fertility,
the ability to produce offspring,
and the growth and maturation of future generations.
Why is this field important?
Today, we have smaller family sizes, and we want to
plan and have families when we want them.
There's an even greater need to be able to produce healthy offspring when we want them.
Birth defects occur in about six percent of all births in humans,
and also there's going to be a background rate in any species that we look at.
The causes of these birth defects hasn't changed much over the years,
I am presenting some data here developed in 1988 by Brent and Holmes, published in Teratology,
which is the journal for the society that studies birth defects
(now called Birth Defects Research and Prevention Society),
you can see from this slide that genetic diseases account
for between 10 and 25 percent of all birth defects.
Unknown causes is the largest group, we still don't know what causes them,
65 to 75 percent of all birth defects are unknown,
although as we identify more genetic diseases that number may get a little lower.
Only about 10 percent of all birth defects appear to have an environmental cause.
Some of those could be from maternal disease states such as diabetes,
we know diabetic women have a higher rate of birth defects in their offspring.
Metabolic deficiency, or if you had too much vitamin A or too little vitamin A in your diet,
you could cause a birth defect, that's classically known.
Mechanical problems in utero, the umbilical cord can get constricted around a limb and
cause a deformed limb, and other accidents can occur in utero.
Then there are drugs, chemicals, and radiation,
which appear to cause less than one percent of all birth defects.
However, when a drug or a chemical or radiation does cause a birth defect
it can be very serious, and it is also very preventable.