Specialized prenatal care and substitution programs improve the perinatal prognoses of pregnant drug-abusers and their infants. Although methadone is well documented, little is known about high-dose buprenorphine (HDB). This prospective, multicenter (n = 35) observational study included 259 women on maintenance during pregnancy: 39% on methadone and 61% on HDB. Major findings were: 46% of them received good prenatal care; 62% had peridural analgesia; 12.3% delivered prematurely (<37 weeks); mean gestational age, 38.6 weeks; mean birth weight, 2822g. Three-quarters of the newborns developed neonatal abstinence syndrome (NAS) beginning at a mean age of 40h, with the mean maximum Lipsitz score of 9.1 at 72 h; half of them were treated, mainly with morphine hydrochloride. No baby died. Newborns were discharged with their mothers (96%) or placed in foster care (4%). Comparing methadone with HDB, respectively, mean age at the maximum Lipsitz score was 81 h versus 66 h (P = 0.066). The perinatal medical and social prognoses for these 259 drug addicts and their infants appeared to be improved by specialized prenatal care and was similar for methadone or BHD substitution during pregnancy.