High levels of prenatal smoking exposure affect sleep patterns in preter...(d to smoking after birth could recover a...),Health

Forty healthy preterm neonates (postconceptional age approximately 33.9 weeks) were recruited from the neonatal intensive care unit at Amiens University Medical Center in France. Mothers were subjectively asked how many cigarettes they had smoked during their pregnancy in order to determine the level of in utero exposure to smoking. Neonates born to mothers who did not smoke at all during the pregnancy were placed in the control group; infants born to mothers who smoked less than 10 cigarettes per day were placed in the low smoking group; and those whose mothers had smoked more than 10 cigarettes per day were placed in the heavy smoking group.

The neonates born to heavy-smoking mothers had a significantly lower mean birth weight than controls. Their average weight of 2.92 pounds was 21 percent less than the average weight of controls, which was 3.69 pounds. Neonates born to mothers who smoked less than 10 cigarettes per day had a birth weight that was 11 percent lower than controls, although this result did not achieve statistical significance.

All children were free of neurological, respiratory, and cardiac disorders and had not received caffeine treatment or oxygen therapy. Neonates whose mothers reported substance abuse or passive smoking were excluded from the study. None of the infants had suffered from sleep deprivation in the 48 hours prior to the sleep recording session.

Infants received overnight polysomnographic recordings in isolated rooms. Researchers measured sleep period time, beginning at the first sleep onset and the ending at the last awakening; the percentage and frequency of wakefulness after sleep onset and total sleep time. Special attention was paid to the number and duration of body movements.

Findings indicate that even after 29.7 days without postnatal exposure to smoking or nicotine, and despite the fact that
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