Parenthood really begins at conception, not at birth. Although such statements are typically used to discourage pregnant women from smoking cigarettes and consuming alcohol, there is evidence that other factors, such as how a mother feels, can influence her child’s health.

A Cambridge research team at the Department of Physiology, Development and Neuroscience, led by Professor Abby Fowden, recently presented strong evidence that high stress levels during pregnancy can affect the growth of a foetus and even its long-term health. To do this, the scientists performed experiments in which they tracked the effect of glucocorticoids in mice. Glucocorticoids are hormones released when mice (and humans) are subjected to environmental or social stress, disease, or pregnancy.

These hormones are produced by the adrenal gland and are important in maintaining a healthy metabolic balance. They have anti-inflammatory effects and decrease body temperature, which helps the body deal with stress and pain. However, a continuous exposure to high glucocorticoid levels is unhealthy. 

The research team gave pregnant mice different doses of glucocorticoids in their drinking water and tracked the development of their offspring. When given in the later stages of the pregnancy, the ability of the placenta to feed the foetus was disrupted, which resulted in lower birth weights and occasional malformations. The team believes that the same relationship between glucocorticoids and foetal development may also apply to humans, since the mechanism of action of these hormones appears to be similar in all mammals. Their research indicates that, even if a mother has a healthy and balanced diet, excessive stress levels may affect the nourishment and proper development of her unborn child. However, a mother who cannot avoid chronic stress may increase her calorific intake to make sure her future baby receives proper nourishment.

Although it is always difficult to make conclusions about the implications for humans of a study performed using mice, it is clear that neither adults nor their unborn children are able to withstand excessive stress. In today’s fast-paced society, research of this type is increasingly important.