Stress during pregnancy is harmful to offspring

About seven years ago, a Manila-based couple visited Maine in the United States. They were both physicians-she an anesthesiologist, and he a surgeon. They were there to take a test to become nurses!

I asked them why they wanted to migrate to the United States. They said they have a son with autism.

At that time I was studying the causes of autism. So I asked the anesthesiologist about her pregnancy, particularly about stress. She said her pregnancy was stressful. Many patients with complicated cases were assigned to her, being the youngest in the group.

From an informal survey in my medical practice, eight out of 10 children with autism, Asperger syndrome, or ADHD (attention deficit hyperactivity disorder) had a mother whose pregnancy was stressful.

Both animal studies and epidemiological human research have shown that gestational stress affects the fetal brain negatively.

Rats and primates, when exposed to unscheduled loud noises during gestation, produce offspring who can’t negotiate mazes. These same offspring cling more often to the parent compared to the offspring whose mother was not stressed.

About 12 years ago, Quebec in Canada experienced an ice storm. A number of communities suffered power failure for a week or more. This event gave medical researchers a good chance to study the effects of stress during pregnancy. They studied two groups: The experimental group was composed of pregnant mothers who were in areas without electricity, and the control group, pregnant mothers in areas with power supply.

The Quebec researchers followed up on the children up to five years and older. They found that the children whose mothers were in the experimental group were delayed in language development and had cognitive difficulties. They also found that the severity of the stress during pregnancy was directly related to the severity of the language delay and cognitive problems. The more stress during pregnancy, the more brain problems.

There is scientific reason to explain the effect of stress during pregnancy. Studies in both animals and humans show that when the mother is stressed during pregnancy, the level of cortisol, the stress hormone, goes up in her blood. Cortisol then goes through the placenta, then to the fetal circulation. When stress occurs during the 15th week of gestation, more of the corticotrophin-releasing hormone (CRH) in the placenta is produced 31 weeks later. Both cortisol and CRH have damaging effects on the fetal brain.

In animal studies, an elevated maternal cortisol level leads to deficits in learning and memory, long-lasting delays in neuromotor development, and distractibility in the offspring.

The brain is the largest functional organ during fetal development. I think prolonged exposure of the fetal brain to an increased level of cortisol is equivalent to posttraumatic stress disorder in adults, and leads to the signs and symptoms of autism, ADHD and other chronic mental problems in children.

Lesson: Let us all give pregnant moms a happy, bright and relaxed environment at home and in the workplace.

Dr. Leonardo L. Leonidas (nonie-leonidas68@ gmail.com) retired in 2008 as assistant clinical professor in pediatrics from Boston’s Tufts University School of Medicine, where he was recognized with a Distinguished Career Teaching Award in 2009. He is a 1968 graduate of the University of the Philippines College of Medicine and now spends some of his time in the province of Aklan.