Warning for moms-to-be
2008-04-15 12:41
New York - A mother's substance use during
pregnancy can mean a smaller brain for her child, according to
a new study in Paediatrics.
Among 35 children 10 to 14 years old, those whose mothers
had used cocaine, drank alcohol, or smoked tobacco or marijuana
while they were pregnant tended to have a smaller head
circumference than their peers who weren't exposed to these
substances prenatally.
The differences seen with use of a
single substance were not statistically significant, but became
so when a child was exposed to two or more of them.
While the findings suggest no single substance has a
"devastating" effect on the foetal brain, Dr Michael J Rivkin
of Children's Hospital and Harvard Medical School in Boston,
the study's lead author, told Reuters Health, they do show that
a combination of them quite possibly will. "There is no smoking
gun," he said in an interview.
Rivkin and his team used an imaging technique called
magnetic resonance imaging to measure the volume of different
types of brain tissue in the study participants, and also
measured head circumference.
Exposure to each single substance
was tied to a smaller head circumference, lower volume of grey
matter (the portion of the brain containing nerve cell bodies),
and lower total brain volume.
While the single exposures did not have a statistically
significant effect, exposure to a combination of two substances
did produce significant reductions in the three measures of
brain size.
The difference grew with the number of
exposures, with children exposed to four substances having the
smallest heads and brains and the lowest grey matter volume.
"Although firm conclusions about the discrete individual
effects of prenatal cocaine, alcohol or cigarettes on brain
volume in the children of our small sample cannot be made,
these data are consistent with a possible, lasting effect of
each and raise concern that exposure to combinations of these
four substances during the prenatal period may have an enduring
effect on brain structure in children," Rivkin and his
colleagues conclude.
Based on the findings, Rivkin said, health professionals
counselling women who are pregnant or thinking of becoming
pregnant should warn them not only about the risks of
individual substances, but inform them that they could be even
riskier in combination.