Vitality

Pregnant Womens' Stress Can Cause Damage To Growing Baby; Relaxation Is Key

Pregnancy Stress Revealed
Stress during pregnancy causes more harm than previously thought. Photo courtesy of Shutterstock

Having a baby can be stressful for some moms-to-be, but too much stress could permanently damage a child’s future health. Researchers from the University of Cambridge studied what happens inside a pregnant woman when she becomes stressed, and published their findings in The Journal of Physiology.

Researchers tested how pregnant mice handled high stress levels, and then saw how it impacted their offspring throughout the pregnancy, and after birth. Twenty mice were given a natural stress hormone known as glucocorticoid for the first half of their pregnancy, and another 31 mice were given the hormones for the second half. A third group of 74 pregnant mice were given nothing — these were the stress-free control mice of the lot.

What researchers observed was worrisome; not only did the stressed out mice eat more than the non-stressed mice, but the stress reduced the amount of glucose that made it to the babies. Glucose is an important energy source produced from the food once it’s digested. How could stress stop the baby receiving a normal, healthy amount of glucose?

Glucocorticoid is secreted by the adrenal glands when the body experiences stress. It pulls energy from the bloodstream and stores it in the body, delaying certain long-term processes that aren’t necessary at the time of the misperceived threat of stress. Feeding, digestion, growth, and reproduction are all put on pause while glucocorticoid works it way through the body, trying to re-establish a critical biological balance known as homeostasis.

"Together with previous work, the findings show that maternal glucocorticoids regulate fetal nutrition," the study’s lead author Dr. Owen Vaughan said in a press release. "Higher glucocorticoid hormone levels in the mother (as seen in stressful conditions) can reduce glucose transport across the placenta and lead to a decrease in fetal weight."

How Does Stress Cause Physical Harm?

Many have heard of the “fight-or-flight” rhyme. It signifies an antiquated but biologically inescapable system that takes over the body when it becomes stressed. Cortisol, adrenaline, and epinephrine are the three major stress hormones released into the body when the brain feels threatened. This innate nervous system trigger was created for humans to run from lions, fight for food, and assess danger for their offspring — not to have their hearts leap when they have a deadline the next day or their babysitter cancels last minute.

Stress is necessary, though. It causes a wide range of physical and mental chain reactions, which topple over like dominoes, and emerge as racing thoughts and blood pumping through organs. In survival mode, a high dosage of cortisol helps maintain fluid balance and blood pressure in order to keep all systems functioning properly, but at a higher speed.

When there’s a healthy exchange of cortisol, it may only take the body a half an hour to return to a normal state. But let’s say there’s constant stress, whether it be over the baby’s future health or the finances a new mother is about to take on, the body will continuously releas cortisol at chronically elevated levels. Overtime, it can cause some serious damage, according to the Mayo Clinic, and now researchers realize it's not just the mother's health at risk.

When researchers observed the pregnant mice that were receiving a regular flow of stress hormones, they found the genes in the placenta began to change quickly overtime. The placenta, which is the baby’s source of food for nine months becomes so altered by maternal stress hormones, researchers actually saw the gene Redd1 change. They believe the gene controls oxygen levels, nutrition uptake, and regulates the growth of the baby. Vaughan said a next set of studies may prove stress levels are so important, they could be permanently changing a child’s nutrition as he grows in his most vulnerable and dependent stage of life.

"Glucocorticoid levels in pregnant women may determine the specific combination of nutrients received by the fetus and influence the long-term metabolic health of their children as a result,” Vaughan said. “This could have implications for women stressed during pregnancy or treated clinically with glucocorticoids, if the mechanisms are similar in humans.”

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