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.