When is the fetus most vulnerable to teratogens?
The embryonic period, during which organogenesis takes place, occurs between implantation at around 14 days to around 60 days postconception. This is usually the most sensitive period to teratogenesis when exposure to a teratogenic agent has the greatest likelihood of producing a malformation.
During what phase of pregnancy is exposure to a teratogen likely to do the most damage?
The developing child is most at risk for some of the most severe problems during the first three months of development. Unfortunately, this is a time at which many mothers are unaware that they are pregnant. Today, we know many of the factors that can jeopardize the health of the developing child.
During which trimester in pregnancy is the developing fetus most susceptible to the effects of teratogens?
During the development of a baby, there are certain organs forming at certain times. If a teratogen has the potential to interfere with the closure of the neural tube, for example, the exposure to the teratogen must occur in the first 3.5 to 4.5 weeks of the pregnancy, since this is when the neural tube is closing.
Can teratogens cause birth defects?
Teratogens are substances or other factors that can cause congenital abnormalities, which are also called birth defects. Usually these abnormalities arise in the third to eighth weeks of pregnancy, when the major organ systems are forming.
How can teratogens be avoided during pregnancy?
If your doctor orders a test with possible radiation exposure during your pregnancy, they must strongly believe that the risk of exposure is less than the risk of an untreated or undiagnosed condition. In most cases, the lower abdomen can be shielded with a protective apron to prevent exposure.
What are 4 teratogens?
Teratogens are classified into four types: physical agents, metabolic conditions, infection, and finally, drugs and chemicals.
What teratogen is most likely to affect pregnancy?
The most common malformations include craniofacial dysmorphisms, cleft palate, thymic aplasia, and neural tube defects. The tranquilizer thalidomide is one of the most famous and notorious teratogens.
What stage are teratogens most harmful?
Time of exposure: Teratogens are most harmful early in pregnancy, starting about 10 to 14 days after conception to about 8 weeks into pregnancy.
What are the most critical stages for exposure to alcohol as a teratogen?
It appears that both early exposure (during the first 2 months of pregnancy) and exposure during the third trimester affect growth. Specifically, effects on head circumference—and, by extension, brain growth—appear to be the most consistent and permanent outcomes of exposure during these two periods.