Induction of pregnant women onto opioid-agonist maintenance medication: An analysis of withdrawal symptoms and study retention

Background: Induction onto buprenorphine during pregnancy may be more challenging than induction onto methadone. This study explores factors predicting withdrawal intensities and compares trajectories of withdrawal during the induction phase between opioid-dependent women randomly assigned to methadone or buprenorphine. Methods: A secondary analysis was conducted on data from 175 opioid-dependent pregnant women inducted onto buprenorphine or methadone subsequent to stabilization on morphine sulfate. ANOVA analyses were conducted to determine differences between mean peak CINA scores by medication and completion status. General linear mixed models were fitted to compare trajectories of CINA scores between methadone and buprenorphine conditions, and between study dropouts and completers within the buprenorphine condition. Results: Both buprenorphine and methadone patients experienced withdrawal categorized as minimal by the CINA scoring system. Significant differences in mean peak CINA scores for the first 72. hours of induction were found between the methadone (4.5; SD= 0.4) and buprenorphine conditions (6.9; SD= 0.4), with buprenorphine patients exhibiting higher mean peak CINA scores [. F (3, 165) = 9.70, p< 0.001]. The trajectory of CINA scores showed buprenorphine patients exhibiting a sharper increase in mean CINA scores than methadone patients [. F (1, 233) = 8.70, p= 0.004]. There were no differences in mean peak CINA scores [. F (3, 77) = 0.08, p= 0.52] or in trajectory of CINA scores [. F (1, 166) = 0.42, p= 0.52] between buprenorphine study dropouts and completers. Conclusion: While mean peak CINA score was significantly higher in the buprenorphine condition than the methadone condition, neither medication condition experienced substantial withdrawal symptoms. Further research on factors related to successful induction to buprenorphine treatment in pregnant women is needed.