Determination of nicotine concentrations in human milk.

A total of 34 samples of human milk from 15 donors was analyzed for nicotine content, using a new method of sample preparation and subsequent quantification by gas chromatography. Nicotine was not found in the six samples of milk from non-smokers. The 28 samples from smokers contained an average of 91 parts per billion (ppb) nicotine (ranging from less than 20 ppb to 512 ppb). While no adverse effects to the infant due to nicotine in human milk have been documented, this method of analysis will allow systematic monitoring of nicotine concentrations in the milk of lactating women. These results should not be used to deter breast-feeding; rather, they offer another reason for mothers to reduce or cease smoking.