Mr. Editor:

Two decades ago Baker gave the concept of Fetal Programming (PF), where he associated the prenatal environment and the development of fetus¹. Consequently, the PF would represent “the induction of fetal responses due to the uterine environment” that will condition functional and structural changes in the fetus itself, with short and long term repercussions⁽²⁾. Consequently, if the prenatal environment is adverse in development, we will possibly have pathologies in extrauterine life¹.

The evidence indicates that processes involved in the development of various functions of complex organic systems would begin long before birth and would shape future health problems².

The FP seems to intervene in genetic and epigenetic factors of the product, there are several noxes that would generate toxic stress (infections, inflammation, mother's mood, hypoxia, hyperglycemia, hypothyroidism, alcohol, drugs, tobacco, drugs, etc.). These noxes would be acting directly and indirectly, both molecularly and cellularly, they alter not only neurological development but also increase the risk of mental illness, metabolic diseases, and immune system involvement⁵.

There are three different types of the stress response: positive, tolerable and toxic. In this case, a very important noxa that would have an impact on PF would be toxic stress, which represents a very important event, product of an intense, frequent and prolonged response to stress adaptation³.

There are many theories raised to trigger this stress such as increased levels of glucocorticoids, nitric oxide, serotonin, etc. Citing only cortisol, the increase in this in the mother, causes the placenta to produce downregulation of the 11B hydroxysteroid dehydrogenase type II enzyme, responsible for converting cortisol into inactive cortisone⁴. Having as an outcome that cortisol passes into the fetal circulation with due consequences⁵. This will be evidenced by alterations in the homeostasis of the fetus from the increased risk of spontaneous abortions, lower birth weight, and premature delivery and even to deregulation of the Hypothalamus axis Adrenal Pituitary of the fetus¹.

The magnitude of these effects would have an impact on the health of the mother, the product and the population since the risk of developing behavioral problems is doubled in the children of mothers exposed to toxic stress⁴. This could explain 17% of the variation in language skills, present lower cognitive development, increased risk of autism, mental illness, anxiety disorders, physical illness, cardiovascular disease, diabetes, vascular strokes, cancer, asthma and autoimmune diseases³.

Because there is little information on FP, it is recommended to promote their research within the perinatal maternal priority line, since many pregnant women in Peru live under high levels of toxic stress. It would be convenient to search if there is an association in our population, as described in other countries so that public health policies can be developed for prevention, dissemination, and treatment.