High Prenatal Stress Slows Toddler Development: A 1998 Ice Storm Provided an Opportunity to Study the Effect of External Stress during Pregnancy

Article excerpt

WASHINGTON -- Two-year-olds whose mothers experienced moderate to high levels of stress during the second trimester of pregnancy had significantly lower IQ scores than did children whose mothers experienced less prenatal stress, Suzanne King, Ph.D., reported at a meeting sponsored by the International Association for Women's Mental Health.

Studies of external stressors on humans are hard to find, and the ice storm that blasted southern Quebec and northern New York in early January 1998 provided an opportunity to evaluate the impact of external stress on the children of women who were pregnant during that time or who became pregnant within 3 months, said Dr. King of the division of social and transcultural psychiatry at McGill University, Montreal.

During the series of ice storms that occurred over several days, power lines were toppled and people went without electricity. The economic cost to the region was approximately $1.5 billion, and at least 25 deaths were attributed to the ice storms, due mostly to fires and carbon monoxide poisoning as people attempted to heat their homes.

The research question was whether the timing and severity of the ice storm during pregnancy affected the cognitive development of children. The initial study included 224 women who were pregnant during the storm or who became pregnant in the 3 months after the storm. All the women lived in suburban or rural areas south of Montreal, a region hit especially hard. Of these, 25% were pregnant with their first child.

Approximately 4 months later, researchers asked the women to complete a questionnaire about their objective exposure to the storm, including threats to their well being, damage to their homes, life changes (such as whether they had to move), and the duration of the stress (such as how long they went without electricity).

The study participants averaged 15 days without electricity during the storm and its aftermath; some went as long as 45 days without electricity. Approximately half of the women moved at least once during the crisis and 15% moved up to five times, either to the homes of friends who had power or to some type of emergency shelter.

Ultimately, 19 children of mothers exposed to low prenatal stress and 39 children of mothers exposed to moderate to high prenatal stress--a subset of the full sample--were evaluated for cognitive development at 2 years of age. …