Pregnancy under high-dose buprenorphine

This study was first conducted to compare the consequences of the use of methadone and high-dose buprenorphine in pregnancy in France and secondly to describe the heterogeneity of women under high-dose buprenorphine. This paper focuses on the second point only.

From October 1998 to September 1999, data on pregnancy, delivery outcomes and neonatal parameters were collected for 251 addicted women on methadone or high-dose buprenorphine (HDB) substitution followed in 35 hospitals and clinics in continental France. Then the data of 159 women who had been taking HDB during pregnancy and had delivered 160 live infants were analyzed.

Most of these women were treated as outpatients by general practitioners. 43% of them belong to what we considered a "hidden population" of drug users: most of them were native French citizens, who lived with the future fathers in their own homes, had at least some secondary education, and were usually not followed in specialized centers for drug addicts. Almost all the women smoked every day during their pregnancies; 20% used heroin during the last 4 weeks preceding delivery; 16% admitted having injected HDB at least once. Notably, neither the severity nor the duration of the neonatal abstinence syndrome (NAS) seemed to be related to the daily doses of the substitution agent. Half of the newborns were treated for NAS, mainly with morphine hydrochloride.

Although two different populations of women were clearly identified, 64 with no social disadvantage and 95 socially disadvantaged, there was no difference between the groups as for the severity of NAS which was only related to the mothers' compliance with a programme of treatment against addiction.