[An appreciation of maternal smoking with high-performance liquid chromatographic determination of maternal and neonatal urinary cotinine].
OBJECTIVE
To study the correlation of urinary cotinine levels in mothers and newborns with the number of cigarettes smoked at the end of pregnancy. Population and methods. We recorded the smoking habits of 123 mothers attending a university maternity clinic and measured urinary cotitine levels in mothers and their newborns. All mothers were Europeans and gave birth to a normal full-term (37 weeks gestation) infant. Cotinine levels were measured with high-performance liquid chromatography from urine samples taken during the 6-hour period prior to or after delivery for the mothers and 24-h after birth for the newborns.


RESULTS
The average cotinine level for non-smoking mothers, for those who smoked one to nine cigarettes a day and heavy smokers (ten or more cigarettes per day) were 0.21, 2.17 and 4.28 mol/l respectively (p<0.001). The average levels in their newborns were 0.04, 0.39 and 1.36 mol/l respectively (p<0.001). Thirteen percent of the mothers who claimed they did not smoke had cotinine levels higher than the significance cut-off (0.3 mol/l). There was a significant correlation 1) between the number of cigarettes the mothers stated they smoked at the end of pregnancy and their urinary cotinine concentrations (cotinine level=0.213 + 0.349 cigarettes, r=0.78, p<0.001); 2) between the number of cigarettes smoked and newborn's urinary cotinine concentration (cotinine level=0.002 + 0.104 cigarettes/day, r=0.81, p<0.001); and 3) between the mother's and the newborn's urinary cotinine concentrations (newborn cotinine=0.027 + 0.219 maternal cotinine, r=0.77, p<0.001).


CONCLUSIONS
The number of cigarettes smoked at the end of pregnancy accounts for roughly 50% of the variance in the mother's urinary cotinine level and that in her newborn at birth. The urinary cotinine concentration in newborns is 3 to 5 times lower than that of their mothers. A woman smoking 3 cigarettes per day has a urinary cotinine concentration of 1 mol/l. The urinary cotinine level in newborns is 1 mol/l for mothers smoking 10 cigarettes per day.
Burguet
A
A
Pédiatrie 2, CHU de Besançon..
Berard
M
M
Woronoff
A S
AS
Roth
P
P
Menetrier
M
M
Vanlemmens
P
P
Schaal
J P
JP
Menget
A
A
D002851:Chromatography, High Pressure Liquid; D003367:Cotinine / Q000652:urine*; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D008431:Maternal-Fetal Exchange; D011247:Pregnancy; D012907:Smoking / Q000652:urine*
D003367:Cotinine