I believe the article was this one:
[
www.springerlink.com]
Though I just read a summary of it in a non-technical article here:
[
www.arc.org]
From that second link:
"College- and graduate-school educated black mothers have a higher infant mortality rate than white moms who didn’t finish high school"
"According to Dr. Michael Lu, assistant professor of obstetrics and gynecology and public health at UCLA, researchers have found that even when they control for such varied factors as poverty, housing, employment, medical risk, abuse, social support and so on, 90 percent of the differences in birth weight between black and white moms remains unaccounted for."