Relax, expectant mothers: It's good for you and your baby
In many societies even today, pregnant women may wear an "evil eye" to
protect their unborn child from bad spirits in their environment.
According to London psychobiologist Vivette Glover, who was in Seattle
recently speaking to nurse scientists at the University of Washington,
they may be on to something.
As head of a multidisciplinary study on the effects of maternal stress and anxiety on the unborn child, Glover has conducted unprecedented research showing possible links between what a woman experiences in the last trimester of pregnancy and the later health of her baby.
According to Glover, who studied biochemistry at Oxford, maternal anxiety has been shown to raise the fetal heart rate, while stress can also greatly activate cortisol production. What does this mean for the unborn child? Plenty, if results from extensive testing in animal models are similar to humans.
Glover explains that cortisol, unlike other hormones a mother produces, is capable of crossing the placenta. She cited one study that showed that extreme stress during the first few months of pregnancy, such as the death of an older child, was linked to an increase in organ defects such as cleft palate and facial malformations. Another study linked stress and anxiety and related behaviors such as smoking or drinking during pregnancy to an increased risk of preterm delivery.
Working during pregnancy, when it is "contrary to the woman's wishes," and thus more stressful, has also been shown to increase the risk of preterm delivery, the researcher notes. She also cites additional studies that link stress or anxiety to low birth weight because of restricted blood flow to the uterus.
Of primary interest to Glover, however, is the result of stress and anxiety on the behavioral development of the child. Using longitudinal data from a study of 10,000 pregnant women living in Avon, England, Glover and her multidisciplinary research team showed that mothers who were anxious at 32 weeks of pregnancy had children who were three times more likely to develop later behavior problems such as hyperactivity or attention deficit disorder.
Although "more research needs to be done," she says, their findings provide a link between maternal anxiety and fetal brain development during the last trimester, when the brain is growing most rapidly. Glover notes that the results are similar with mothers who are depressed during this period, although anxiety has a bigger effect.
But haven't women always experienced stress during pregnancy? What about during wartime, for example? Glover, professor of perinatal psychobiology at Imperial College, explains that she posed this question to her own mother, who experienced the bombing raids on London, and she believes the difference is all in the perception.
"Being part of a stressful event where everyone is working together and there is a feeling of being on the right side is different from today," she explains, "when so many women feel helpless or alone in their anxiety."
Glover also postulates that prenatal stress can affect laterality, making the offspring more likely to be left-handed, and that it may possibly be linked with an increased incidence of autism and learning disorders.
So how much stress is too much?
While noting that "women worry too much during pregnancy as it is," Glover also feels it is important to get the word out to health care providers about the risks from stress. That's because, unlike genetic or socioeconomic factors, "this is something we can do something about," she says, noting that massage, yoga, exercise, light treatment and social support are all potentially useful in reducing maternal stress. She cited an intervention using hypnotherapy and also passive relaxation that showed dramatic decreases in maternal heart rate and cortisol production.
"Many interventions may well be helpful, and we ought to introduce them now, although it is also important to carry out parallel research to find out which actually have the most effects on outcome," Glover says. She also believes that stress-reducing techniques should be carried over to the post-natal period, when depression can also be very damaging.
"Our society needs to increase public health resources for women before and after birth, and we should be much more flexible about factors such as women working," she adds.
Nurse scientists at the UW Center on Infant Mental Health, which sponsored Glover's visit to Seattle, have developed many tested interventions to improve the health and well-being of women during pregnancy. Some of these are available online at www.son.washington.edu/centers/steppingup/.
Kathleen Dannenhold is a writer and public relations specialist who served as Director of Communications for the UW School of Nursing before joining the staff of the Center on Infant Mental Health and Development (CIMHD).