Breastfeeding and smoking: short-term effects on infant feeding and sleep

The present experimental study was designed to determine how breastfeeding from a mother who smokes affects infants in the short-term.

Fifteen mother-infant dyads were tested on 2 days separated by 1 week. Mothers smoked (not in the presence of their infants) on one test day and refrained from smoking on the other. For the next 3.5 hours, infants breastfed on demand. Sleep and activity patterns were monitored by placing an actigraph on the infants' leg, and milk intake was determined by weighing the infants before and after each feeding. The nicotine content of the milk was measured to determine the dose of nicotine delivered to the infants.

Although there was no significant difference in breast milk intake, despite the taste changes in the milk, infants spent significantly less time sleeping during the hours immediately after their mothers smoked (53.4 minutes), compared with the session when their mothers abstained from smoking (84.5 minutes). This reduction was attributable to shortening of the longest sleep bout and reductions in the amounts of time spent in both active sleep and quiet sleep. With greater doses of nicotine delivered to the infant, less time was spent in active sleep.

An acute episode of smoking by lactating mothers altered infants' sleep/wake patterning. Perhaps concerns that their milk would taste like cigarettes and their infants' sleep patterning would be disrupted would motivate lactating mothers to abstain from smoking and to breastfeed longer.