Placenta barrier to cocaine, study finds Calgary Herald June 11, 1994 by Mark Lowey TORONTO - Developmental problems in children exposed to cocaine prior to birth may be due more to neglect at home than the drug's longterm effects, a study suggests. "Cocaine babies," a term used by the popular media to label children with problems, is a misnomer, said Dr. Carmine Simone, researcher at the Hospital for Sick Children in Toronto. He co-authored the study to be published in the American Journal of Obstetrics and Gynecology, with Dr. Gideon Koren, head of clinical pharmocology at the hospital. Prenatal exposure to cocaine may be a merker of other problems at home, such as child abuse, neglect and substance abuse by parents, Simone said. In fact, researchers found that the placenta in the womb may actually help protect the fetus from cocaine abuse by the mother. Using placenta recovered from full term births, researchers devised apparatus that simulates conditions in the womb when the mother takes cocaine. "We can mimick the way women take drugs," Simone said. "It's a model for what's happening." The placenta is usually discarded after birth, he noted, adding the study was conducted according to strict ethical guidelines and no fetuses were involved. Results showed the placenta appears to act as a barrier to cocaine. It is able to absord about one-third of the administered dose, with about one-third getting through that would affect the fetus. The rest is eliminated. Simone said this situation may be due to the way cocaine is taken, in staggered "hits" as the high wears off. The placenta appears to metabolize and eliminate the drug between the hits. Children of cocaine abusers show no proven lasting physiological or developmental effects due to their experiences in the womb, said study co-author Koren. A study involving three Toronto hospitals found about six per cent of new borns, or one in 16, showed exposure to cocaine in the final three months before birth. But if the placenta buffers exposure, this would help explain why only 10 of 120 of the babies needed resuscitation or other intensive care. Other research shows cocaine-exposed newborns are smaller than average and much less healthy.