Five times as many pregnant women were using opiates in 2009 compared to 2000, while during the same period the number of newborns with a diagnosis of drug withdrawal syndrome, neonatal abstinence syndrome has increased 3-fold, researchers from the University of Michigan Health System, Ann Arbor, Michigan, reported in JAMA (Journal of the American Medical Association). The authors added that hospital charges related to neonatal abstinence syndrome (NAS) have increased considerably. According to a recent USA-wide study, 16.2% of pregnant teenagers and 7.4% of pregnant mothers aged from 18 to 25 took illegal drugs, the researchers explained. Neonatal abstinence syndrome, or NAS is a set of problems that newborns experience when they are exposed to addictive prescription or illegal drugs while they were in their mother\'s uterus. NAS occurs because the mother, while pregnant, took addictive drugs (prescription or illegal), such as cocaine, diazepam, marijuana, opiates (heroin, codeine, methadone), barbiturates, or amphetamines. The drugs pass through the placenta and reach the embryo/fetus. Along with the mother, the baby becomes addicted. When the problem is related to alcohol, doctors may use the term Fetal Alcohol Syndrome. The authors explain that low birth weight and higher mortality are also associated with illicit drug use during pregnancy, especially opioids.60% to 80% of newborns who had been exposed to methadone or heroin while in the womb are reported to have NAS signs and symptoms. However, there are not national estimates on how many newborns in the USA have NAS symptoms due to maternal opiate use. Stephen W. Patrick, M.D., M.P.H., M.S., and team carried out a study to look at the patterns in the national incidence of NAS and maternal opiate usage at the moment of childbirth, and to characterize trends in national health care expenditures linked to NAS during the first nine years of this century.