Source: Video and Images Created by Amanda Soderlind
Welcome to this lesson today on developmental disorders. Today we are going to be discussing the causes and effects of various developmental disorders. So the first thing we need to define is what a teratogen is. And a teratogen is an agent that can cause birth defects. So teratogens can be things like drugs, infections, deficiency of nutrients, viruses, et cetera. So it's an agent that can cause a birth defect.
So let's take a look at our first defect labeled here, spina bifida. So spina bifida is a birth defect that is caused by a deficiency of nutrients. So the teratogen in this case would be nutrition. So spina bifida is when the neural tube doesn't close, and therefore, part of the spinal cord may be exposed on the baby.
And this is due to a lack of folic acid during development. So folic acid is an important nutrient that mothers need to make sure they get enough of while they are pregnant because folic acid is important in the development of the baby. So if they don't get enough folic acid, this neural tube is not going to close, and then they can end up with spina bifida.
These next two right here, rubella and toxoplasmosis, are two disorders that can be caused by infections. So the teratogen in this case, then, would be an infection. So rubella actually is specifically a virus. And what it does is it inhibits proper development of organs of the baby if the mother contracts the virus while pregnant. So if a pregnant mother contracts rubella, it will have an impact on her baby because the organs of that baby might not properly develop.
And then toxoplasmosis is caused specifically by a parasitic cyst. And these parasitic cysts can affect the fetus and cause birth defects or miscarriage. So this is caused through exposure to cat feces.
So basically, when mothers are pregnant, they're warned to stay away from any cat feces. If they have a cat in the house, they're supposed to stay away from the litter box, because this parasitic cyst is spread through cat feces. And basically this parasitic cyst can cause birth defects or even a miscarriage if the mother is exposed to them. So that's toxoplasmosis. It's not super common, but it is something that can happen.
And then the last disorder we're going to talk about today is fetal alcohol syndrome, sometimes also called FAS, fetal alcohol syndrome. So fetal alcohol syndrome is a disorder that causes mental retardation if a mother drinks alcohol while pregnant. So there are actually various different types of drugs that can lead to developmental disorders. And a mother should never do any type of drugs while pregnant because of the increased risk of these disorders.
But the one we're going to focus on today is just with alcohol. So that's fetal alcohol syndrome. So if a mother drinks alcohol while pregnant, it can cause this mental retardation. And this can vary a little bit depending on the severity. So some cases of fetal alcohol syndrome are more severe than others. So this lesson has been an overview on various types of developmental disorders and their causes.
Source: Video and Images Created by Amanda Soderlind
Welcome to this lesson today on detecting birth defects. Today, we will be looking at various methods that are used in order to detect birth defects in an unborn fetus. So nowadays, we have lots of different types of technologies that help us detect these birth defects in an unborn fetus. And the three we're going to be talking about today are listed on the screen here.
So we're going to start by talking about Chorionic Villus Sampling, also sometimes abbreviated as CVS. So chorionic villus sampling is a sampling that can be used to detect for birth defects as early as the eighth week of pregnancy. And basically, what happens with this type of sampling is a tube that has a suction and is inserted into the vagina, up into the uterus, and then will suck out a small sampling of chorionic villus cells-- and these cells are a part of the placenta-- which will then be tested for any birth defects at that time.
The next type of way that we can test for birth defects is with amniocentesis. So with this type of technology, it can be used between the 14th and the 16th week of pregnancy. So it's testing the amniotic fluid. So it's testing the amniotic fluid that the fetus is during pregnancy. So this amniotic fluid contains sloughed off cells of the fetus, and if you take a sample of that amniotic fluid, they can test some of those sloughed off cells for any types of birth defects.
So, basically, what happens is that a needle is inserted into the mother's belly and then into that amniotic fluid. And then some of it is pulled out and then tested. So this is one way that can be used in order to test for these birth defects by using the cells of the fetus that are found in the amniotic fluid.
And then preimplantation diagnosis is another way we can test for birth defects. So this type of diagnosis actually is involved with in vitro fertilization. So it's screening of an embryo that has not yet been implanted into the uterus. So that's why we're talking about preimplantation. So it happens usually around the eight cell stage of development.
So they will take one of those cells, test it for any birth defects, and if it comes out clear, they will then implant that embryo into the mother's uterus. So it's screening the embryo conceived by in vitro fertilization for these genetic defects before it has been implanted into the uterus, so preimplantation.
So as with all of these different types of ways to detect birth defects, there are definitely some benefits associated with it. A parent would know in advance if their unborn child has any sort of birth defects, and they could prepare themselves for that. But it also has some risks associated with it as well.
Some types of ways to detect birth defects, especially with amniocentesis, since it is a little bit more invasive, can lead, rarely but sometimes, to infections and things like that. And with a chorionic villus sampling, one of the risks associated with that is that the child can end up with an abnormal number of fingers and toes because of that process. So there definitely are some risks and benefits associated with it that the parent would have to weigh before going through with any of these types of technologies. So this lesson has been an overview on detecting birth defects.