The metabolism of nicotine in cigarette smokers during pregnancy

Abstract

The urinary excretion of nicotine and its metabolites, nicotine-l '-N-oxide and cotinine, were determined for 40 pregnant and 30 non-pregnant smokers. The pregnant subjects participated in a longitudinal study over their last trimester in order to describe variations in nicotine metabolism with gestational age. No significant relationship was found between the level of excretion of the nicotine metabolites and infant birthweight for the pregnant smokers; nor was evidence found for the preferential accumulation of cotinine compared to nicotine-l '-N-oxide for pregnant compared to non-pregnant smokers. The longitudinal study demonstrated a significant drop in the nicotine-l '-N-oxide excretion level over the 29th to the 32nd weeks of gestation for all six subjects examined over this period.Tests demonstrated that this decrease in the nicotine-l '-N-oxide level was not due to an unusual decomposition effect in the urine.

Nicotine and Related Alkaloids

“…Although disappearance from plasma and elimination of nicotine and its metabolites are not affected by pregnancy in humans, the distribution of nicotine is altered in this state (Klein and Gorrod, 1979). Nicotine has been shown to cross the placenta of several species.…”