Can Stress Hurt Your Fetus?

Just last month researchers warned that drinking more than the equivalent of one "tall" Starbucks coffee a day while pregnant may double the risk of miscarriage. Now there's another scary-sounding study for moms to be: researchers at the University of Manchester in the United Kingdom and the University of Arhus in Denmark report in this week's issue of the Archives of General Psychiatry that women who experience an extremely stressful event during early pregnancy may significantly increase their risk of giving birth to children who go on to develop schizophrenia. The researchers examined the records of 1.38 million Danish women who gave birth between January 1973 and June 1995, identifying women whose relatives were seriously ill or died immediately before or during their pregnancies, and then followed their offspring from age 10 to see who developed schizophrenia. They found that women who dealt with the death or serious illness of a relative in the first trimester had up to 67 percent greater risk of having a schizophrenic child compared with women who did not experience such a traumatic event.

As shocking as that statistic may seem, doctors say pregnant women should not panic. Only an estimated 1 percent of the U.S. population develops schizophrenia, and even Dr. Kathryn Abel, the University of Manchester psychiatrist who co-authored the study, says, "The biggest risk factor is still family history." Still, studies like these raise troubling questions about how much a pregnant woman's mental health affects her unborn child and what can be done to avoid adverse effects from events she cannot control. To find out, Karen Springen spoke with Dr. Maurice Druzin, chief of maternal-fetal medicine at Stanford University Medical School and chief of obstetrics at the Lucile Packard Children's Hospital. Excerpts:

NEWSWEEK: Is there anything pregnant women can do to mitigate the effects of a stressor, like a family death, that's out of their control?
Dr. Maurice Druzin: These life stressors are not under our control. What's under our control are appropriate diet, exercise and attempts to keep the stresses down. So if somebody does have a major life event, it would be important for them to seek early counseling and, if necessary, to be on an appropriate antidepressant … But to go tell some poor patient that because her mother died that her kid is going to be schizophrenic is irresponsible … Every week I have somebody come to me who's had a bad outcome. They're always in tears because they think it's something they've done [to cause it]. This kind of stuff is to me very dangerous because it's never put into perspective … You know, you can never get away from stress. We need a little bit of stress to survive.

So women don't need to eliminate stress entirely?
Living is stress. Even baseline living is stressful, particularly if you've got a child.

Is it true that pregnant women who experience extreme stress are at increased risk of delivering preemies, or babies with birth defects or low birth weight?
The absolute correlation between stress and preterm delivery is not proven by well-done studies. I'm not aware of any significant study that will say some life stress is going to have an increased risk of birth defects. The issue with preterm birth is probably a little tighter correlation. But it's such a multifactorial thing.

How can stress cross the placental barrier?
[The thinking is,] fetuses that are stressed in utero have higher levels of stress hormones, and when they become adults they turn out to have higher risk of hypertension, cardiovascular disease and other degenerative diseases like that. This comes from a lot of good data from World War II in Holland, where there was a lot of starvation and babies were very small. Those babies were found to have a higher risk of cardiovascular disease and hypertension. It's thought that there's reprogramming of the fetus early. The in utero events are seen 30 or 40 years later in adult life as an inappropriate response to stress hormones.

So this schizophrenia study makes some sense?
There's no question that maternal reaction to different stresses and disease may affect fetal development, but it may not be seen immediately upon birth. It's called the Barker hypothesis, which is: fetal programming [reveals itself] later on in adult disease. This probably is part of the same spectrum of what happens. It's not clear why and what exactly happens. There's a lot of work going on about corticotrophin-releasing hormone, a stress hormone. There's some evidence that increased maternal stress would lead to increased levels of stress hormones in the fetus because they cross the placental barrier. There are a lot of theories about it. And there may be some truth to it.

These effects seem most profound in the first trimester, right? Why?
They are probably greater in the first trimester. It's early in the first trimester because organogenesis is occurring—when all the organs are being formed. Most of the organs are formed by the end of the sixth and seventh week. After that it's more organ growth. There's a vulnerability in the beginning, where you have actual organs being formed. People need to take folic acid supplementation before they're pregnant to prevent neural tube defects … But if the mother starts doing things like drinking and [taking drugs], it can not only have an effect in the first part of the pregnancy, it can also have an effect on the last part.

So it's not true that pregnant moms can become more lax after the first trimester?
The bottom line is you should maintain a healthy lifestyle throughout pregnancy. In the second part of pregnancy, there may not be a structural abnormality, but there may be some effect on brain growth and heart growth.

We've had a flurry of studies recentlysuch as the Kaiser report on the link between caffeine and miscarriage. How worried should women be?
There was a recent study that said exactly the opposite. What do you tell people?

What should women actually worry about?
I just tell people, everything in moderation—but no alcohol and no cigarettes.

How can a pregnant woman stay calm when faced with such anxiety-provoking information?
She can exercise, which is a very, very good mechanism for staying calm, because it releases endorphins. It needs to be in moderation … Start off with half a mile, go to a mile, go to two miles, whatever. You'd be amazed at how quickly you can get into shape, just with walking.

What do you wish pregnant women knew?
I wish they would all have a healthy lifestyle before they get pregnant. Get into an exercise program and a balanced diet program. Take their prenatal vitamins with folic acid. Those are the three things they can do that are simple, straightforward, not expensive, not complicated. If they could come into pregnancy in good shape, with a balanced diet, that's probably the best preparation they can have.