Permanent stress of the mother affects the baby via the amniotic fluid

If the mother is stressed for a long time during pregnancy, the concentrations of stress hormones in the amniotic fluid increase. On the other hand, a short-term stress situation does not necessarily have an unfavorable effect on the development of the unborn child. This has been proven by researchers from Zurich.

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If a expectant mother feels strongly stressed over a longer period of time, it may increase the risk for the unborn child to later develop a mental or physical illness - such as an attention deficit / hyperactivity disorder (ADHD) or cardiovascular disease. How exactly stress reaches the baby in the womb is not fully understood. The Swiss scientists have discovered that mental stress of the mother can change the metabolism in the placenta and also influence the growth of the unborn child.

Stress hormone acts on growth of the fetus
When stressed, the human body releases hormones to deal with the higher levels of stress, such as the so-called corticotropin-releasing hormone (CRH), which subsequently causes the stress hormone cortisol to rise. This mechanism also persists during pregnancy, and the placenta, which supplies the fetus with nutrients, can also release the stress hormone CRH. As a result, it enters the fetal circulation and the amniotic fluid in small quantities. From animal studies it is known that this hormone can stimulate the development of the unborn child: it is increasingly released when the growth conditions in the womb are unfavorable. This should increase the chances of survival in view of an early birth. Under certain circumstances, this can also have negative consequences. If the growth is accelerated too much, this can be done at the expense of a differentiated maturation of the organs.

Short-term stress - no effect
How does mother's mental stress affect the release of stress hormones in the placenta? The research team examined 34 healthy pregnant women who underwent amniocentesis in prenatal diagnosis. Such an examination represents a stress situation for the expectant mothers, her body spills cortisol at short notice. To determine whether the placenta releases stress hormones, the researchers compared the cortisol level in maternal saliva with the level of CRH in the amniotic fluid - and found no relationship.

Longer loads in the amniotic fluid measurable
Quite different are the results of ongoing stress, which was determined by means of a questionnaire for the diagnosis of chronic stress: If the maternal burden lasts longer, the CRH level in the amniotic fluid is increased. And this higher concentration of stress hormone in turn accelerated the growth of the fetus. (BDH)