Babies born to mothers with high maternal stress hormones or who smoked during pregnancy are at an increased risk for nicotine dependence later in life, says a new study published in the journal Biological Psychiatry.
Smoking during pregnancy has long been considered a public health risk because of the adverse effects of smoking on a developing baby. Mothers who smoke while pregnant increase their risk of miscarriage, stillbirth, premature birth, and low birth weight. Babies born to mothers who smoked are at an increased risk of developing respiratory (lung) problems as well as other health issues.
Despite the well-documented risks of smoking during pregnancy, an estimated 13 to 30 percent of pregnant women continue to smoke.
Now a new 40-year longitudinal study led by researchers from the Centers for Behavioral and Preventive Medicine at The Miriam Hospital in Providence, Rhode Island suggests that daughters born to mothers who smoked during pregnancy have an increased risk of nicotine addiction in adulthood. Prenatal exposure to maternal stress hormones also predicts nicotine dependence in daughters — but not sons — later in life.
To investigate the increased risk of nicotine independence from maternal smoking and maternal stress hormones, the researchers used data from a large, national, long-term project that began in 1959 that included over 50,000 pregnant women. The children of the women in the project were followed by researchers for 40 years.
For the present study, the researchers looked at 1,086 mothers and their 649 daughters and 437 sons. For the mothers, the researchers looked at hormone levels (cortisol and testosterone) during pregnancy and smoking status. For the children, the researchers looked at smoking status.
According to the study, elevated prenatal cortisol exposure and exposure to maternal smoking during pregnancy increased the risk of nicotine dependence in female offspring. The same increased risk was not found for male offspring or for the hormone testosterone.
Explains Dr. Laura Stroud, the first author on the study:
“While maternal smoking during pregnancy has been shown to be an independent risk factor for nicotine dependence, we didn’t really know which pathways or mechanisms were responsible. Most prior research involving biological mechanisms had been conducted in animals not humans. Our study suggests 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 concern.”
The results of this study show that vulnerability for certain health problems are affected by sex differences. Adds Dr. Stroud:
“Our findings highlight the particular vulnerability of daughters to long-term adverse outcomes following maternal stress and smoking during pregnancy. 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. Also, cortisol and nicotine may affect developing male and female brains differently. Furthermore, if daughters of smoking mothers are more likely to grow up nicotine dependent, the result is dangerous cycle of intergenerational transmission of nicotine addiction.”
Summarizes Dr. John Krystal, the editor of Biological Psychiatry:
“These new data may help us to focus our attention on individuals at greatest risk for later smoking. It is interesting that female, but not male, offspring seemed to be at greatest risk. Sex differences in the vulnerability to smoking are important and merit further study.”
Based on the results of this study, pregnant women who are expecting girls should additionally be counseled on the increased risks based on sex differences of smoking during pregnancy.
A Daughter’s Risk of Nicotine Dependence Increased by Maternal Stress Hormones and Maternal Smoking: http://www.medicalnewstoday.com/releases/271059.php
Prenatal Glucocorticoids and Maternal Smoking During Pregnancy Independently Program Adult Nicotine Dependence in Daughters: A 40-Year Prospective Study: http://www.biologicalpsychiatryjournal.com/article/S0006-3223(13)00679-3/abstract
City Girl Smoking Cigarette: http://www.freeimages.com/photo/1151820