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Chemical substances

Teratogenic substances, consumed by the mother during pregnancy, can damage the embryo in its development. Medicines and environmental toxins comprise the largest class of teratogenic substances. After the thalidomide catastrophe deformities induced by medications have become much rarer. Caution must, though, be exercised before taking any unsupervised medicine during the pregnancy because only very little is known about the interactions of various medications in the embryo. The trend to alternative medicines such as the use of a harmless-appearing phyto-therapeutica can have disastrous consequences to the fetus. Ginko biloba, for example, contains a large concentration of cholchicine that is known to be poisonous for dividing cells.
The consumption of alcohol must also be mentioned - it is known with certainty to be a teratogenic substance.

Possible mechanisms for the fetal alcohol syndrome are:

  • The alcohol induced production of superoxide-radicals that oxidize the cell membranes and thereby can cause cytolysis.
  • The neural ridge cells are disturbed in their emigration.
  • Alcohol directly hinders cellular adhesion.
Fig. 23 - Frequency of alcohol embryopathies

Fig. 23

 The frequencies of the alcohol embryopathies per year in various countries.
How severe they are depends on the stage of the maternal alcoholism.

Nicotine abuse during the pregnancy mainly leads to deformities if a genetic predisposition is present. Under certain circumstances nicotine is also a neuro-teratogenic substance. Furthermore, nicotine probably has an influence on placental vessels, which in turn can have negative effects on fetal nourishment.

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Animal models show that nicotine is a neuro-teratogenic substance. It disturbs the functioning of specific neurotransmitter receptors in the brain, altering their activity. However, because there exists a close relationship between the cholinergic and the catecholaminergic systems in the brain, nicotine affects various nerve-transmitter systems and thus not only on the momentary development in the fetal brain but, further, also on the beginning programming of entire transmitter systems. These changes happen not only in the CNS (central nerve system) but also in the peripheral autonomic nerve system. A consequence is that through deficient reaction to hypoxia the brain also experiences increased hypoxic damage retroactively. Probably some of the SIDS and perinatal difficulties can be derived from this mechanism.

In addition to the chemical substances just mentioned, new chemical combinations (200 - 500 substances) to be used as pesticides, cosmetics, etc. are being produced constantly and reliable information about toxicity is not available for many of them.

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There is probably no greater controversy in the field of environmental toxicology as that of whether pesticides trigger breast cancer or if they are responsible for the decline of the sperm count among the men in the population or possibly even for the elevated rate of deformities in wild animals.
By all means, further investigations must analyze the exact amount and the consequences of today's environmental pollution because they may well be quite severe. Through further progress in molecular research into such pollution, the precise mechanisms can be better understood and this could then function as a corrective influence in our efforts to save our environment.

We must not only speak about the possible toxicity of new substances, but also about the excessive consumption of substances, such as vitamin A that, in themselves, are necessary for life. Of vitamin A one knows that when taken excessively during pregnancy it can lead to damage of the embryo/fetus. Thanks to its excellent effects on severe acne, it is employed in the treatment of this condition (e.g., in the form of Accutane ®) and can thereby cause severe damage to the baby, if an unplanned pregnancy occurs.

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Damages that result from excessive consumption of retinol (vitamin A) during a pregnancy:

  • Missing or deformed ears
  • Missing jaw or one that is too small
  • Disorders of jaw formation (split jaw)
  • Disorders of formation of the aortic arch
  • Missing thymus
  • Deformities in the CNS