Effects of Prenatal Stress on Developing Mice Have Implications for Humans


Researchers are increasingly looking into the effects of prenatal stress on developing fetuses. Depending on environmental stressors experienced by mothers while pregnant, at a time when they should ideally be relaxed and enjoying the services of a New Jersey maternity photographer, their babies may have serious problems in early childhood. Unfortunately, this is when they should be enjoying a cuddle buddy blanket, and later on, when they may raise children of their own. A study recently performed by neuroendocrinologist Megan Holmes, Ph.D., and colleagues, identified an enzyme involved in the fetal response to stress. In addition, the researchers found that babies may be adversely effected by high levels of glucocorticoid hormones, such as cortisol. Below is more information on these findings.

The Enzyme That Breaks Down Cortisol

During pregnancy, both the mother and the developing infant produce an enzyme known as 11ß-HSD2 that breaks down cortisol to prevent it from harming the fetus while it develops. This enzyme is found in both the brain of the developing fetus and the mother’s placenta. To test the function of 11ß-HSD2 on the developing fetus, the researchers created mice that didn’t have the enzyme and monitored them throughout pregnancy. Without the protection of 11ß-HSD2, the developing fetuses grew less and later showed a range of mood disorders in response to the high levels of cortisol to which they were exposed in the womb.

Research Is Still Early

At this time, scientists aren’t fully clear on how cortisol might affect fetuses in relation to levels of 11ß-HSD2. However, the placentas in mice without 11ß-HSD2 were both smaller and less able to let nutrients through to the fetus. This might be a major reason for the harmful effects of a lack of the enzyme. Besides this, the early data shows that abnormal programming of the fetus happens regardless of nutrient delivery. Once the scientists better understand the interplay between the issues that cause abnormal fetal programming, they hope to be able to identify ways to reverse the problems caused by the mood disorders that result. This will require studying humans.

Immediate Benefits

The researchers hope that this new study will help spread the word about problems caused by malnutrition, abuse and feelings of grief during pregnancy. Better support and monitoring will help prevent this from becoming a problem. The effects of high glucocorticoid hormones on fetal development also hold major implications for modern healthcare for mothers who are considered high-risk for premature delivery. At present, glucocorticoids are routinely given to these mothers in order to strengthen the lungs of their fetuses and improve their chances of survival after being born. This study highlights the need for better monitoring of this type of treatment.

The scientists say that puberty is another time when stress hormones are known to adversely affect development. Rats that are stressed during this time tend to develop mood problems as adults. Because teenagers have more intense responses to emotional stress, including fear, control of stress during this time may help them avoid mood disorders later in life.

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