Daughters exposed to their
mother's stress hormones in the womb may be more likely to become
nicotine-dependent later in life, a new long-term study suggests. It also found
that girls whose mothers smoked during pregnancy were at higher risk for
eventual nicotine dependence.
Researchers analysed data
from 649 women and 437 men who were followed for 40 years after being born to
mothers whose hormone levels and smoking status were recorded during pregnancy.
The results showed that
exposure to elevated levels of the stress hormone cortisol in the womb and
having a mother who smoked during pregnancy was linked to an increased
likelihood that daughters, but not sons, would be at raised risk for nicotine
dependence as adults.
The study was published in
the January issue of the journal Biological Psychiatry.
Read more: Pregnancy smoke linked to asthma in teens
Analysis of the study results
highlight the particular vulnerability of daughters to long-term adverse
outcomes following maternal stress and smoking during pregnancy," first
author Dr. Laura Stroud said in a journal news release.
"We don't yet know why
this is, but possible mechanisms include sex differences in stress hormone
regulation in the placenta and adaptation to prenatal environmental
exposures," said Stroud. She is a researcher with the Centres for Behavioural
and Preventive Medicine at the Miriam Hospital in Providence, R.I.
"Also, cortisol and
nicotine may affect developing male and female brains differently," she
Spreading from one generation to the next
It may be that the
daughters are more likely to pass on a similar risk of nicotine dependence to
their own daughters, making a cycle that goes from one generation to the next,
Stroud also said the
findings suggest "that maternal smoking and high stress hormones represent
a 'double-hit' in terms of increasing an offspring's risk for nicotine
addiction as an adult. Because mothers who smoke are often more stressed and
living in adverse conditions, these findings represent a major public health
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