Breastfed Babies May Sleep Less When Mothers Smoke
NEW YORK - Nursing mothers who smoke may be cutting their infant's nap times short, a new study shows.
Babies whose mothers smoked shortly before breastfeeding napped about 20 minutes less over the following three and a half hours than those whose mothers had abstained from cigarettes for several hours, Dr. Julie A. Mennella and colleagues found.
"The greater the dose of nicotine in their milk, the greater the disruption of sleep," Mennella, of the Monell Chemical Senses Center in Philadelphia, told Reuters Health.
In 2003, the American Academy of Pediatrics took nicotine off the list of drugs that breastfeeding women should avoid, she pointed out. Studies have shown that breastfeeding can protect infants from some of the health consequences of cigarette smoke exposure, such as respiratory illness. "If you smoke, we still want you to breastfeed," Mennella said, given that the benefits outweigh the known risks.
However, there is very little information on how exposure to nicotine in mothers' milk affects infants, she added.
To investigate, Mennella and her team recruited 15 mother-infant pairs. All of the women had smoked before and during pregnancy, although they cut down while they were pregnant. At the time of testing, the women averaged about 10 cigarettes a day, but the amount smoked ranged from 1 cigarette to 30 cigarettes daily, the team reports in the medical journal Pediatrics.
On one day, after abstaining from cigarettes for at least 12 hours, each mother smoked a cigarette away from her child, while wearing a lab coat and gloves. After taking off the protective gear and washing her hands, the woman then returned to her baby and breastfed the infant on demand over the next 3.5 hours. On the second day of the experiment, separated from the first by a week, the mothers didn't smoke before feeding their babies.
On non-smoking days, the babies napped for 84.5 minutes, on average, compared to 53.4 minutes on the smoking days, the researchers found. The more nicotine they received in breastmilk, the less time they spent in active sleep.
Mennella pointed out that smokers tend to wean their babies earlier, which could be because of the sleep disruptions she and her colleagues observed.
Smoking women can reduce their infant's exposure to nicotine by waiting two hours after having a cigarette to nurse, she added, because the amount of the chemical peaks in the blood 30 minutes to an hour after the cigarette is smoked.
Perhaps the findings, along with previous research by Mennella and her team that found cigarettes lend "a very strong, pronounced flavor" to breast milk, might encourage smoking mothers to cut down or quit while nursing, she added.
SOURCE: Pediatrics, September 2007.