Neonatal withdrawal syndrome, Michigan, 2000-2009.

Background: Neonatal withdrawal syndrome, which is associated most frequently with opioid use in pregnancy, is an emerging public health concern, with recent studies documenting an increase in the rate of U.S. infants diagnosed.

Purpose: This study examined neonatal withdrawal syndrome diagnosis among Michigan infants from 2000 to 2009 and hospital length of stay (LOS) between infants with and without the syndrome for a subset of years (2006-2009).

Methods: Michigan live birth records from 2000 to 2009 were linked with hospital discharge data to identify infants with neonatal withdrawal syndrome. Linked data were restricted to infants born between 2006 and 2009 to examine the difference in hospital LOS between infants with and without the syndrome. Multivariable regression models were constructed to examine the adjusted impact of syndrome diagnosis on infant LOS and fit using negative binomial distribution. Data were analyzed from July 2011 to February 2012.

Results: From 2000 to 2009, the overall birth rate of infants with neonatal withdrawal syndrome increased from 41.2 to 289.0 per 100,000 live births (p<0.0001). Among infants born from 2006 to 2009, the average hospital LOS for those with the syndrome was between 1.36 (95% CI=1.24, 1.49) and 5.75 (95% CI=5.41, 6.10) times longer than for infants without it.

Conclusions: Diagnosis of neonatal withdrawal syndrome increased significantly in Michigan with infants who had the syndrome requiring a significantly longer LOS compared to those without it.