Mothers Who Smoke May Increase Their Newborns' Discomfort

A new research study suggests that maternal smoking may increase the level of distress of newborns.

Studies have consistently found that prenatal cigarette smoke exposure is associated with increased rates of behavior problems, irritability, attention-deficit/hyperactivity disorder, the risk of violent offenses, conduct disorder, adolescent onset of drug dependence, and the risk for criminal arrest in offspring. This study adds another potential negative outcome to the list of reasons for mothers to stop smoking while pregnant.

Most of the effects of tobacco either during pregnancy or on postnatal outcomes are attributed to nicotine. However, smoking is associated with reduced monoamine oxidase A (MAO-A) activity, enzymes that degrade brain neurotransmitters in smokers. Prenatal smoke exposure-induced low MAO-A activity in fetal life may dysregulate brain neurotransmission, creating a potential vulnerability to develop behavioral disorders later in life. This dysregulation can occur with or without interaction with nicotine's effect on the developing brain.

French scientists compared blood biomarkers of MAO-A activity in smoking and non-smoking pregnant women and in the cord blood of their newborns. They also assessed the newborns' comfort level during their first 48 hours of life. They found that MAO-A activity is reduced both in pregnant smokers and in their newborns. The newborns of smoking mothers also showed significantly more discomfort than those of non-smoking mothers, potentially related to MAO-A inhibition.