Methadone use in pregnancy: evidence of progression in the severity of addiction.

The number of opiate users is well documented; however, the severity of opiate use has received little attention. This retrospective study in a North of England hospital updates the progression in the severity of addiction in pregnancy. Patients treated were reviewed and the doses of prescribed methadone documented. Historical data were also used for comparison. The severity in addiction in pregnancy was assessed by the woman's drug usage expressed as the daily dose of prescribed methadone at the end of pregnancy. From 2001 to 2008 there was an increase in the mean dose of methadone prescribed at delivery from 28.2 ml/day in 2001 to 57.9 ml/day in 2008. Historically, the use was 27.3 ml/day in 1992-1996 and 32.4 ml/day in 1997-2003. No trend was noted in the number of pregnant users. In conclusion, we observed no recent increase in the number of methadone users presenting, but the severity of drug usage in pregnancy has increased.