NEW YORK (Reuters Health) - Both black and white women with symptoms of depressive mood prior to becoming pregnant have increased risk for preterm birth; but black women have twice the risk as white women, researchers report in the Journal of Women's Health.

"The black-white disparity in preterm birth may be in part a consequence of different exposures to depressive mood prior to pregnancy," Dr. Amelia R. Gavin, at the University of Washington in Seattle, told Reuters Health.

However, previous investigations of this association were inconclusive, leading Gavin and colleagues to assess links between race, preterm birth, and prepregnancy depressive mood among 555 women who were 24 years old on average when they gave birth.

The researchers used data collected from 1990 through 1996 for a larger long-term investigation of heart disease risk, in which the women had participated.

In the current study, 18.1 percent of the 249 black women gave birth prior to 37 weeks gestation. This preterm birth rate was more than twice the 8.5 percent rate seen among the 306 white women.

Prepregnancy depressive mood was also more prevalent among black versus white women - 9.4 versus 7.2 percent. Depression scale examinations conducted in 1990 to 1991, showed black women with higher depressive mood scores than white women - 13.0 versus 9.5.

Furthermore, black women's risk for preterm birth remained more than twice that of white women's risk when Gavin's team allowed for other factors associated with preterm birth, such as body weight and sociodemographic characteristics.

"Reproductive outcomes must be viewed in light of women's health over the entire life-course, as well as during pregnancy," Gavin said.

These current findings suggest "the experience of cumulative health disadvantages or 'weathering,'" may play a role in increased risk for preterm birth, Gavin notes.

She and colleagues, therefore, suggest replication of this study in a larger population of women.

SOURCE: Journal of Women's Health, June 2009.