teratogen
Anything that causes defects and abnormalities in the fetus is called a teratogen.
Congenital malformations are anatomical or structural disorders that are present at birth. Two main reasons cause this abnormality.
1- Genetic factors
2- Environmental factors
Many genetic and environmental factors may play a role in causing common abnormalities.
In the first two weeks of pregnancy, dealing with teratogenic factors leads to the death of the fetus rather than causing abnormalities.
The prevalence of abnormalities in the fetus is much higher than in the newborn, which means that severe abnormalities often lead to spontaneous abortion in the first weeks (6 to 8 weeks).
During the period (15 to 60 days) when organs are being formed, teratogenic factors cause severe abnormalities.
Knowing the teratogenic factors provides the opportunity to avoid dealing with them during the sensitive period of pregnancy in order to prevent the occurrence of abnormalities caused by them. Some of them are introduced below.
Nicotine:
Nicotine does not cause abnormalities, but it prevents the fetus from reaching the fetus and increases the chance of premature birth, and in addition, by disrupting the blood supply, it may cause mental retardation.
Alcohol:
It causes developmental disorders, mental retardation, classic changes in the face and cardiac anomalies, even drinking a small amount of alcohol can cause these changes, and drinking a large amount can cause brain disorders in the fetus at any gestational age.
Tetracycline:
Tetracycline causes deposits in bones and teeth and leads to yellowing of teeth and disruption of bone growth. Tetracycline can cause these changes even after birth.
Anticonvulsant drugs including phenytoin and valproic acid:
It is an anticonvulsant drug and causes delay in fetal growth; microcephaly (small brain and skull); Mental retardation and hypoplasia of the last digit.
Chemotherapy drugs:
These drugs are highly teratogenic and should not be used as much as possible. But sometimes it is forced to be used in the last trimester.
Vitamin A and its derivatives:
It is highly teratogenic in humans even with a low dose. From the second to the fifth week of pregnancy is an important period for creating these effects. The most common abnormalities they cause; Head and face disorders and cleft palate; Aplasia of the thymus and defects in the spinal tube.
Tranquilizers such as thalidomide and phenothiazines:
causes disorders in the formation of organs; not forming the inner and outer ear; Homa Njiuma; cardiac abnormalities; and disorder in the formation of the urinary system; will be These changes usually happen between 24 and 36 days after conception.
Infectious agents:
When they pass through the placenta, they can cause all kinds of developmental disorders and mental retardation in the fetus. Rubella causes cataracts; Heart abnormalities and deafness. If the mother suffers in the early stages of pregnancy; The fetus will be affected. Most embryos that are caught in the fourth or fifth week; They will have signs of contact with the virus. The probability of abnormalities in the case of collisions in the second and third trimesters is greatly reduced, but the risk of mental retardation and deafness still exists.
Cytomegalovirus is the most common infection during the fetal period. Infection in the first trimester often leads to spontaneous abortion. Infection in the following months causes disruption of intrauterine growth; small organs; blindness; Mycocephaly: mental retardation and hepatosplenomegaly
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This post is written by deture