A new report provides both encouraging and discouraging data regarding the use of alcohol, cigarettes and illicit drugs by pregnant women and new mothers, according to a statement from the U.S. Substance Abuse and Mental Health Services Administration (SAMHSA), part of the U.S. Department of Health and Human Services.

According to national survey data, most women are paying attention to warnings about the dangers that substance use during pregnancy can pose to the developing fetus -- and are avoiding harmful substances during pregnancy.

However, many new mothers go back to alcohol, cigarettes and illicit drugs soon after they give birth.

"Alcohol, cigarettes, and illicit drug use during pregnancy can cause poor pregnancy outcomes and early childhood behavioral and development problems, and use after pregnancy exposed children to a variety of negative effects. These problems can limit a child's potential, are costly and 100 percent preventable," said SAMHSA's Acting Administrator Eric Broderick.

The new SAMHSA data stem from national surveys on drug use and health collected from 2002 through 2007 involving a nationally representative sample of 113,000 women ages 18 to 44 years, about 6,000 of whom were pregnant at the time of the surveys.

The combined data indicate that past month alcohol use was highest for women who were not pregnant and did not have children living in the household (63.0 percent) but comparatively low for women in the first three months of pregnancy (19.0 percent), and even lower for those in the second trimester (7.8 percent) or third trimester (6.2 percent).

Similar patterns were seen for marijuana, cigarette and binge alcohol use. Binge drinking is defined as having five or more drinks at one time or within a few hours at least one day in the last 30 days.

According to the survey data, many women quickly return to alcohol, cigarette and illicit drug use following childbirth. For example, marijuana use was higher among recent mothers with children younger than 3 months old in the household (3.8 percent) than for women in the third trimester of pregnancy (1.4 percent), "suggesting the resumption of use among many mothers in the first 3 months after childbirth."

Effective interventions to reduce substance use during and after pregnancy could improve the health and well-being of infants and new mothers, the SAMHSA report concludes.