A new study says that women who suffer from pre-pregnancy depressive mood, face heightened risk of premature birth.
However, black women have nearly two times the odds of having a pre-term birth compared to white women, said Amelia Gavin, a University of Washington assistant professor of social work and lead author of the study.
"Preterm births are one of the most significant health disparities in the United States and the overall number of these births increased from 10.6 percent in 2000 to 12.8 percent in 2005," she said.
The study found no cause and effect link between giving birth prematurely and depressed mood, but Gavin believes that the higher pre-term birth rate among blacks might be the result of declining health over time among black women.
For the study, premature birth referred to any child born after less than 37 weeks of gestation, which normally ranges from 38 to 42 weeks.
The data for the study was drawn from a larger longitudinal investigation looking at the risks for cardiovascular disease among more than 5,000 young adults in four metropolitan areas in the US.
Between 1990 and 1996, 555 women in the larger study gave birth. These women were the subjects in the depression-premature birth study.
"At this point we can't say that pre-pregnancy depressive mood is a cause of preterm birth or how race effects this association. But it seems to be a risk factor in giving birth prematurely and higher pre-pregnancy depressive mood among black women compared to white women may indirectly contribute to the greater odds of preterm birth found among black women," said Gavin.
It was found that 18.1 percent of the black women in the study had a preterm birth compared to 8.5 percent of the white women.
The difference could be the result of what Gavin calls "weathering", or accelerated declines in health due to repeated socioeconomic and political factors.
"What some people experience by being black takes a toll on the physiological system, and over time wear and tear that occurs across neural, neuroendocrine and immune systems as a result of chronic exposure to stressors lead to health disparities for blacks. Some of this may manifest itself in premature birth and low-birth weight," said Gavin.
The study has been published in the Journal of Women's Health.