Lower serum osteocalcin levels in pregnant drug users and their newborns at the time of delivery.

Osteocalcin was evaluated by radioimmunoassay at the time of delivery in mothers and in the umbilical arteries of newborns in a group of pregnant drug users (eight heroin users and seven cocaine users) and compared with findings from a group of normal mothers and their newborns (N = 18). Drug users had lower osteocalcin values than did the normal women (1.3 +/- 0.7 versus 2.7 +/- 0.8 ng/mL, P less than .001); and infants of drug users had lower values than normal infants (14.1 +/- 3.8 versus 19.0 +/- 4.0 ng/mL, P less than .005). The birth weights of drug users' infants were smaller (3160 +/- 402 versus 3591 +/- 374 g, P less than .05) and there was a significant negative correlation (P less than .001) between osteocalcin and drug intake during pregnancy, but no changes in osteocalcin dependent on the type of drug used. These results suggest a toxic effect of these drugs on the osteoblast, which could account for the lower birth weights and skeletal alterations reported in the infants of drug users.