Why is exposure to toxins especially dangerous during the first trimester?
Substances or agents that can interfere with normal embryonic development and cause malformations or defects to an embryo or fetus are called teratogens. When a pregnant women is exposed to toxic chemicals, the fetus will usually also be exposed, via the placenta.
What toxins can cause developmental or birth defects?
Toxic environmental chemicals can cause birth defects
- Lead.
- Mercury.
- Arsenic.
- PCBs.
- Chlorine.
- Methyl Ethyl Ketone.
- Cadmium.
- Pesticides.
Why is the 1st trimester the most dangerous?
Harmful exposures during the first trimester have the greatest risk of causing major birth defects. This is because many important developmental changes take place during this time. The major structures of the body form in the first trimester. These include the spine, head, arms and legs.
When is fetus most susceptible to toxins?
The fetus is most vulnerable during the first 12 weeks. During this period of time, all of the major organs and body systems are forming and can be damaged if the fetus is exposed to drugs, infectious agents, radiation, certain medications, tobacco and toxic substances.
Why do teratogens cause birth defects?
During this time, teratogens can cause neural tube defects such as spina bifida. Some organs are sensitive to teratogens during the whole pregnancy. This includes the baby’s brain and spinal cord. Alcohol affects the brain and spinal cord, so it can cause harm at any time during pregnancy.
When do teratogens affect the fetus?
Teratogens are thought to have the ability to effect the fetus about 10 to14 days after conception. During the development of a baby, there are certain organs forming at certain times.
What are some teratogens that affect the fetus?
Known Teratogens
- angiotensin converting enzyme (ACE) inhibitors, such as Zestril and Prinivil.
- alcohol.
- aminopterin.
- androgens, such as methyltestosterone (Android)
- busulfan (Myleran)
- carbamazepine (Tegretol)
- chlorobiphenyls.
- cocaine.
What are long term effects of teratogens?
These include, but are not limited to, the following: Abnormal development produced by a teratogenic exposure is manifested as death, malformation(s), growth retardation, or a functional disorder.
When is a teratogen 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. Genetics: Sometimes, the pregnant person’s or the baby’s unique genetics protect them or make them more vulnerable to certain teratogens.
What are the common teratogens and their effects?
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 are teratogens give 5 examples?
Common teratogens include some medications, recreational drugs, tobacco products, chemicals, alcohol, certain infections, and in some cases, uncontrolled health problems in the birthing parent. Alcohol is a well-known teratogen that can cause harmful effects on the fetus after exposure at any time during pregnancy.
What drugs are teratogenic?
Drugs that are capable of acting as teratogens include:
- ACE (angiotensin converting enzyme) inhibitors such as:
- Acne medication isotretinoin (Accutane, Retin-A).
- Alcohol ingested chronically or in binges.
- Androgens (male hormones).
- Antibiotics tetracycline (Achromycin), and doxycycline (Vibramycin), and streptomycin.