Neonatal Abstinence Syndrome (NAS) has risen to epidemic rates in the U.S. and is under-reported. The data for 28 states, reported in this article, indicates these trends. The use of ICD-9 codes are discussed in diagnostic data of in-patient cases. The codes have helped place a diagnosis for these cases, yet it is difficult to determine from data whether the opioids are prescribed or illicit use. The focus of the article deals with the marked increase in incidence and the CDC's involvement in addressing this as a public health issue.
http://www.cdc.gov/mmwr/volumes/65/wr/mm6531a2.htm