COCAINE USE DURING PREGNANCY - SENSITIVE DETECTION BY HAIR ASSAY

Objectives. This paper compares the sensitivity of two tests of cocain e use, interview and urine test, with that of a radioimmunoassay of ha ir. Methods. Interviews and hair samples were provided by 397 obstetri c patients in one New York City hospital; urine samples were obtained in 377. Of these patients, 241 were receiving prenatal care (were regi stered) and 156 delivered without prenatal care (were unregistered). T he 241 registered patients were derived from 400, comprising all repor ting use of cocaine ever (''ever-users''), all reporting use by the fa ther but not themselves (''lifestylers''), and a sample of women who w ere neither ever-users nor lifestylers. The 156 unregistered patients were derived from 352 women interviewed at delivery, unselected for re ported use. Results. Thirty-two percent reported ever using cocaine, 4 5% of these within 6 months before interview. Urine tests were positiv e in 20%, hair tests in 59%. The estimated sensitivity of thr hair tes t (92%) was 3.1 times higher than that of the urine test (95% confiden ce interval [CI] = 2.5, 3.8) and 4 times higher than that of reported use in the past 6 months (95% CI = 3.2, 5.0). Conclusions. Self-report and urine tests alone miss most of cocaine users during pregnancy. Ha ir tests greatly improve detection and thus can enhance evaluations of the effects of prenatal cocaine use on fetal and child development.