Smoking related to plasma leptin concentration in pregnant women and theirnewborn infants

Leptin, a hormone produced in adipose tissue and placenta, is potentially i mportant in relation to energy metabolism and growth. We investigated the e ffect of cigarette smoking on maternal plasma leptin concentration during p regnancy. and on plasma leptin concentration and weight among infants up to 13 wk of age. Plasma leptin concentration was measured in women in week 18 (n = 203) and week 35 (n = 164) of pregnancy, while cotinine (nicotine met abolite) was measured in plasma sampled from mothers in well; 35 of pregnan cy (n = 159). Leptin concentration was also measured in plasma from the umb ilical cord (n = 133) and from 4-wk-old (n = 129) and 13-wk-old (n = 130) i nfants. There was no difference in plasma leptin concentration between smok ing and non-smoking mothers at 18 wk and at 35 wk of pregnancy. Plasma coti nine concentration was higher in smoking than in non-smoking mothers, and a negative correlation between plasma cotinine and leptin concentrations was found. The leptin concentrations in umbilical cord plasma were similar, al though the birthweights of newborns from smoking mothers were significantly lower than those from nan-smoking mothers. The plasma leptin concentration s were similar between the two groups also at 4 wk of age, At 13 wk of age, infants of smoking mothers had significantly higher plasma leptin concentr ations than infants of non-smoking mothers. Conclusion: Our results indicate that a lower birthweight of neonates among smoking mothers is not due to altered plasma leptin concentration.