The study investigated substance use patterns among 192 pregnant substance-using women to determine whether there were ethnic differences regarding drugs of choice, frequency and recency of use, and severity of use. Substance use patterns differed across ethnic groups. Alaska Native women were more likely to choose alcohol as their primary drug of choice and less likely to choose cocaine. White women used a wider variety of substances in their lifetime and used substances more often. Alaska Native women had an earlier age of onset of use and more blackouts. The most common pairing of drugs of choice for Alaska Native women was alcohol and marijuana. For white and other women, the most common pairing was cocaine and alcohol. The study confirms prior findings that women are using cocaine to a significant degree and may be catching up with men regarding substance use choices that are favoring illegal over legal substances. These findings also suggest that prevention and intervention efforts should be tailored to the target population. Tables, references