NEW YORK (Reuters Health) - African-American newborns may be more likely than their white counterparts to be screened for prenatal drug exposure, even in the absence of risk factors for it, a study at one medical center suggests.
Research shows that newborns admitted to neonatal intensive care units (NICUs) have a higher-than-average risk of having been exposed to illegal drugs during pregnancy. If staff suspect prenatal drug exposure, they may test an infant's urine or feces for evidence of it.
Some NICUs, though not all, have specific guidelines on what factors should trigger a newborn drug test.
The new study, published in the journal Pediatrics, shows that even at a center with such guidelines, there are racial discrepancies in rates of drug screening.
The study team examined medical records for more than 2,100 newborns admitted to the NICU at the University of Rochester Medical Center in New York in 2005 and 2006.
They found that among infants who met at least one of the NICU's criteria for drug screening, those born to African-American mothers were more likely to be tested: 35 percent, versus 13 percent of infants born to white mothers.
The same pattern was seen among newborns who did not meet the screening criteria. Among these infants, 5 percent of African Americans were tested for prenatal drug exposure, while only 1 percent of white newborns were.
Yet, when infants were screened, black babies were less likely to test positive for drug exposure. Four percent screened positive, versus 12 percent of white newborns who were tested.
The reasons for the racial discrepancy in screening rates are not clear, according to senior researcher Dr. Carl D'Angio, director of neonatal clinical research at the university.
One possibility, he told Reuters Health, is that the NICU's screening criteria were too complex.
D'Angio explained that the unit's guidelines included a "laundry list" of potential risk factors for staff to consider in deciding to drug test. Some of those factors, he said, have been strongly associated with higher odds of prenatal drug exposure -- such as a documented history of mothers' drug use, and a lack of prenatal care.
But some other criteria the NICU used have not been strongly linked to prenatal drug exposure, such as abnormalities of the urinary tract or genitals.
The complexity of the criteria, D'Angio said, may have made them hard to use objectively, and resulted in staff sometimes relying instead on "subjective cues" of maternal drug use -- which might have fed the racial discrepancy.
That is just a theory, however. "We don't know what drove the behavior," D'Angio said. "We can only describe the behavior."
The findings did lead the Rochester NICU to simplify its drug-screening criteria, D'Angio said. The guidelines now emphasize a smaller number of factors that are most strongly predictive of prenatal drug exposure -- including limited prenatal care and a history of drug use in the mother.
The hope is that the changes will improve compliance with the guidelines, and reduce any tendency to use subjective judgment, according to D'Angio.
He said the current findings suggest that other NICUs need to be aware of the potential for unequal application of newborn drug screening, and try to minimize those odds.
Newborn drug screening, D'Angio and his colleagues point out, "entails significant privacy, social, and legal risks for families."
Laws vary by state, but positive drug tests can result in families being reported to child protective services or, in some cases, law enforcement.
Pediatrics, June 2010, online May 17, 2010.