Magazine article Clinical Psychiatry News

First-Trimester Stress May Prompt Early Delivery

Magazine article Clinical Psychiatry News

First-Trimester Stress May Prompt Early Delivery

Article excerpt

RANCHO MIRAGE, CALIF. -- Mothers who experience high levels of stress during early pregnancy appear to convey distress signals to their fetuses, prompting their fetuses to eventually produce high levels of hormones that speed delivery.

The phenomenon suggests the presence of a "placental clock" for parturition that may be set months before the onset of labor, said Curt A. Sandman, Ph.D., professor and vice chair of psychiatry at the University of California, Irvine.

The pattern was seen in a prospective evaluation of pregnant California women who happened to be enrolled in a comprehensive study of pregnancy outcomes when the magnitude 6.7 Northridge earth-quake struck early the morning of Jan 17, 1994, killing dozens of people and leveling thousands of homes.

Those subjects who were in their first trimester showed highly elevated levels of stress hormones, but those in their third trimester had much lower levels of stress hormones, Dr. Sandman said at a conference on sleep in infancy and childhood sponsored by the Annenberg Center for Health Sciences.

Months later, women who had been exposed to the stress of the earthquake early in pregnancy were significantly more likely than other mothers to deliver early.

"An early maternal message that it's a hostile world primes the placental clock for a CRH [corticotropin-releasing hormone] response later," he said.

Subsequent studies in 550 consecutive pregnant subjects confirmed a consistent link between high levels of maternal cortisol early in pregnancy and elevated levels of placenta-derived CRH in the third trimester. Elevated CRH not only seems to speed delivery, but also appears to have profound consequences on the fetal response to stimuli and, later, a child's response to stress.

The complex interaction between maternal stress, fetal CRH, pregnancy outcomes, and infant and childhood behavior has been the target of studies conducted over more than 12 years as part of the women and children's health and well-being project at UCI, Dr. Sandman said.

More than 1,000 women and 600-700 infants have been enrolled thus far in studies that begin with extensive prenatal assessment that starts at about 10 weeks' gestation. Neuroendocrine profiles assess the maternal stress axis, while ultrasound examinations and studies of fetal behavior continue throughout pregnancy.

Infant stress examinations begin with the routine first heel-stick test received in the nursery, when researchers take advantage of a naturally occurring opportunity to evaluate salivary cortisol. …

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