Teratogenic effect: features

Teratogenic effect of drugscauses the appearance of defects, as well as anomalies in the development of the child because of their use by the mother in the course of pregnancy. Teratogenesis develops under the influence of factors acting externally on the fetus' emerging organism, also possible under the influence of hereditary diseases.

Than it is caused?

Teratogenic action is due to the passagedrugs or products of their transformation through the barrier between the uterus and the placenta, as a result of which the processes of formation of the organs and tissues of the embryo are disrupted.

Critical periods

Different stages of pregnancy are differentdamage associated with the chronological formation of body structures - these are critical periods. The most dangerous in terms of the development of serious violations are the first 2-3 months of pregnancy. It should be noted that in earlier periods, under the influence of such factors, disturbances also occur in the developing organism, but they are incompatible with life: miscarriage (spontaneous abortion). Critical periods for different organs are different: 23-28 day of intrauterine development is important for the brain, 23-45 day for the organ of vision, limbs are formed on the 28-56 day and so on.

What factors cause?

The following factors cause a teratogenic effect: drugs, infections (rubella, herpes, cytomegalovirus, parvovirus, syphilis, toxoplasmosis), metabolic disorders in pregnant women (endemic goiter, decompensated diabetes mellitus, prolonged hyperthermia, androgen-producing tumors), drugs (androgens, methotrexate, captopril, enalapril, iodides, thiamazole , tetracyclines, thalidomide, valproate, warfarin, busulfan), ionizing radiation (radiation therapy for cancer, radioactive iodine therapy, radioactive fallout) and much more.

Features of the impact

These factors influence with some peculiarities. The teratogenic effect is due to the dose. In addition, before the influence of any factor in the subthreshold values ​​of defects in the fetus is not formed. Teratogenic effect in different biological species and even in different representatives of the same species can be different, which is associated with the individual features of metabolism (absorption, distribution and excretion in the mother's body and direct penetration through the utero-placental barrier). However, when exposure to the mother's infection, it is impossible to determine the threshold dose.

Spreading of factors

Teratogenic factors are widely encountered inenvironment. As a result of the research it was found that a woman during pregnancy takes about 3-4 medicinal substances. In addition, pregnant women can contact different harmful compounds at work or at home. The teratogenic effect of drugs should be established in studies: the relationship between the direct impact of the factor and the appearance of a defect with confirmation of epidemiological data must be proved. In addition, the influence of the factor must coincide with the critical periods.