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This article has been peer reviewed. It is the authors' final version prior to publication in Journal of Pediatrics Volume 157, Issue 3, May 15, 2010, Pages: 428-33, 433.e1. The published version is available at DOI: 10.1016/j.jpeds.2010.03.033. Copyright © Elsevier Inc.


OBJECTIVE: To estimate the relationship between maternal methadone dose and the incidence of neonatal abstinence syndrome (NAS).

STUDY DESIGN: We performed a retrospective cohort study of pregnant women treated with methadone for opiate addiction who delivered live-born neonates between 1996 and 2006. Four dose groups, on the basis of total daily methadone dose, were compared (160 mg/d). The primary outcome was treatment for NAS. Symptoms of NAS were objectively measured with the Finnegan scoring system, and treatment was initiated for a score>24 during the prior 24 hours.

RESULTS: A total of 330 women treated with methadone and their 388 offspring were included. Average methadone dose at delivery was 117+/-50 mg/d (range, 20-340 mg/d). Overall, 68% of infants were treated for NAS. Of infants exposed to methadone doses160 mg/d, treatment for NAS was initiated for 68%, 63%, 70%, and 73% of neonates, respectively (P=.48). The rate of maternal illicit opiate abuse at delivery was 26%, 28%, 19%, and 11%, respectively (P=.04).

CONCLUSION: No correlation was found between maternal methadone dose and rate of NAS. However, higher doses of methadone were associated with decreased illicit opiate abuse at delivery.

Table 1_Demographic variables for 185 mothers enrolled in a methadone treatment program.doc (27 kB)
Table 1. Factors limiting the comparability of studies on methadone maintenance therapy and NAS.

Table 2_Neonatal demographics and clinical variables by gestational age at birth group for 204 neonates.doc (38 kB)
Table 2. Maternal demographics according to maternal methadone dose

Table 3_Systematic univariate analysis of the affect of variables on length of treatment in 204 neonates treated for NAS.doc (39 kB)
Table 3. Indices of methadone maintenance and substance abuse

Table 4_Multivariate analysis of variables p 0.2 for all births (n=201).doc (31 kB)
Table 4. Indices of neonatal abstinence syndrome according to maternal methadone dose

Table 5_ Multivariate subanalysis of births 32 weeks and last UDS positive for methadone only.doc (40 kB)
Table 5. Multivariate analysis of treatment for neonatal abstinence syndrome based on methadone dose

Table 6.docx (13 kB)
Table 6. Multivariate analysis of variables predictive of treatment for neonatal abstinence syndrome