Newborns' cord blood plasma cotinine concentrations are similar to that of their delivering smoking mothers.

BACKGROUND: In utero exposure to constituents of tobacco smoke has perinatal and postnatal health consequences. Umbilical cord plasma cotinine levels have been shown to correlate with self-reported daily number of cigarettes at the end of pregnancy, but the exact relationship between maternal and newborn plasma cotinine (and nicotine) is unknown. METHODS: Concentrations of cotinine, nicotine's main metabolite, were determined in venous blood of delivering mothers and in arterial umbilical cord blood of their newborns at birth. Data from eighteen mother-newborn dyads were analyzed. RESULTS: The mothers smoked 95.1 (SD=96, range 10-420) cigarettes the week preceding delivery. Their mean plasma cotinine concentration at delivery was 106 ng/mL (SD=53, range 17-245) and the newborns' mean umbilical cord plasma cotinine was 88.2 ng/mL (SD=53, range 10-198, p<0.001). The difference can be explained by the elimination time of around 6h which occurred between sampling in mothers and in umbilical cord blood. Arterial umbilical cord blood plasma cotinine was highly associated with that of the smoking mothers: y=0.79x+0.97, Rsq=0.95, p<0.001. CONCLUSIONS: Maternal and newborn plasma cotinine concentrations are strongly associated. There is probably no placental barrier for plasma cotinine between pregnant mothers and their newborns. Lack of a placental barrier for cotinine (and probably nicotine) can partially explain smoking related perinatal disorders.

Reduced monoamine oxidase A activity in pregnant smokers and in their newborns.

BACKGROUND: Tobacco smoking is associated with reduced monoamine oxidase A (MAOA) activity. Smoking-associated low MAOA activities in pregnancy and in newborns may have negative perinatal and postnatal consequences. We aimed to compare, in everyday clinical conditions, biomarkers of MAOA activity in smoking (SPW) and lifetime nonsmoking pregnant women (NSPW) and in cord blood and to assess the newborns' behavior during the first 48 hours of life. METHODS: Thirty SPW and 29 NSPW in their second trimester of pregnancy were included. Plasma MAOA dependent metabolites of norepinephrine: dihydroxyphenylglycol; dopamine: homovanillic and dihydroxyphenylacetic acid; and serotonin: 5-hydroxy-indol acetic acid were measured at the end of the second trimester, at delivery, and in arterial cord blood along with plasma cotinine. The newborns' discomfort was evaluated every 8 hours by a standardized questionnaire. RESULTS: The SPW smoked, on average, 73 cigarettes per week at the end of second trimester and 80 cigarettes per week at delivery. Mean plasma cotinine was 84 ng/mL, 105 ng/mL, and 95 ng/mL at the end of second trimester, at delivery, and in cord blood, respectively (NSPW < 10 ng/mL). Plasma markers of MAOA activity, in particular those reflecting dopamine's catabolism, were significantly lower in SPW and in the arterial cord blood of their newborns than in NSPW and their newborns. Newborns of SPW showed significantly more facial discomfort than those of NSPW. CONCLUSIONS: Smoking is associated with MAOA inhibition in pregnant women and in their newborns at birth. Further studies are needed to estimate the behavioral significance of these findings.