Breastfeeding Mothers Who Smoke May Disrupt Babies' Sleeping Patterns

Women who smoke cigarettes while breastfeeding may disrupt infants' sleep with their breast milk, according to a study published in the journal Pediatrics.

In the study conducted by the Monell Chemical Senses Center, researchers found that infants exposed to the chemical nicotine through breast milk were more likely to have disruptions in their sleep patterns than infants breastfeeding from non-smoking mothers.

Julie A. Mennella, a psychobiologist at Monell, lead the study from the Monell Chemical Senses Center in which researchers observed the feeding behavior and sleep patterns of breastfed infants between the ages of two and seven months over the course of two days. Each of the mothers were current smokers who had abstained from smoking for at least 12 hours. On the first day, mothers smoked one to three cigarettes immediately before the observation period while refraining from smoking on the second day. Nicotine, the key ingredient in cigarettes, is a stimulant associated with many long-term developmental deficits in learning and behavior. In the study, nicotine levels were measured in the mother's breast milk before each feed to determine how much nicotine was passed to each infant.

Researchers found that infants sleep time declined from an average of 84 minutes from non-smoking days to 53 minutes when they fed on smoking days, a 37% reduction in sleep. It was also observed that the infants consumed the same amount of milk on both days. This could mean that they didn't mind the tobacco flavor in breast milk. Mennella thinks that early experiences with tobacco flavor during breastfeeding may increase its appeal later in life. This is consistent with the fact that children whose mothers smoke are more likely to smoke as teenagers.

In a previous study by Mennella, researchers found that nicotine levels in breast milk peak 30 to 60 minutes after smoking one or two cigarettes and eventually clear after three hours. This means that mothers who smoke can time their breastfeeding sessions to minimize nicotine exposure to their child.