A team of researchers from the Miriam Hospital in Providence, Rhode Island have conducted studies is that aimed to discover the effects of smoking during pregnancy and how this impacts the stress response of newborn infants.
Results show that mothers who smoke during gestation are more likely to produce babies with lower stress response, significantly lower level of stress hormones, and an alteration in the genes that regulate the passage of stress hormones between the mother and the fetus. Lead researcher Dr. Laura Stroud from the Centers For Behavioral and Preventive Medicine at the same facility said that, "Our results suggest that these newborns may not be mounting adequate for mental response to daily stressors. Their stress systems may not be prepared for the stressors of daily life. This may be particularly detrimental in babies born to mothers who lack resources in parenting skills and whose babies may encounter more daily stressors."
Data from the national Health statistics office show that there are approximately one in 10 pregnant women in the United States to continue smoking despite their pregnancies. The rate is higher among poor, young, and undeserved mothers. This habit also results in babies with low birth weight, have a higher risk of health complications, and who are more likely to be born premature.
Dr. Stroud continued to explain the impact of smoking during pregnancy saying, "One possibility is alterations in stress hormones and at the genetic changes in DNA. We were interested in stress hormones because alterations in stress hormones have been linked to both smoking and behavior problems and because maternal stress hormones during pregnancy exert potent long-term effects on offspring. In particular, we sought to investigate effects of smoking during pregnancy on the newborn stress hormone cortisol." The research showed that infants from smoking mothers had lower levels of cortisol, which researchers believe could be linked to the development of behavioral problems and nicotine addiction for these children later on in their lives.