Teratogenic Effect

The teratogenic effect (from Greek teras — monster and genes — creating) is the ability of environmental factors (viruses, drugs, radiation) to cause severe developmental disorders of the fetus, leading to congenital defects (anomalies), miscarriage, or stillbirth.

Etiology and pathophysiology

The mechanism of teratogenesis involves direct damage to fetal cells or disruption of their division and migration processes. The extent of the damage is directly dependent on the gestational age.

The most dangerous period is cellular-tissue differentiation and organogenesis (from the 3rd to the 10th week), when the primary organ systems are laid down.

Infectious agents act as powerful teratogens. They exhibit a tropism for rapidly dividing cells, affecting vital tissues of the developing embryo or fetus:

• neuroectoderm;
• vascular endothelium;
• cardiomyocyte precursors;
• optic vesicle cells.

Exposure to these tissues leads to developmental disruptions of organs, systems, and body parts (for example, partial or complete absence of limbs, brain, heart, eye malformations).

Clinical significance

In infectious disease management, knowledge of teratogenic risks is essential for managing pregnant women. Infections contracted early pose the highest risk for severe anomalies.

To mitigate teratogenic risks, the following medical approaches are employed:

• Use of FDA classification — allows for the assessment of prescribed medications based on their potential danger to the fetus;
• Vaccination during pregnancy planning — doctors recommend vaccines against ‘teratogenic’ infections (primarily rubella and chickenpox), as it is the only reliable method to prevent viral exposure to the embryo if the mother comes into contact with an infected person.