Influences of maternal smoking and fetal sex on maternal serum oestriol, prolactin, hCG, and hPI levels.

A total of 222 pregnant women had repeated hormone assays between 20 weeks and delivery; 86 of the women were smokers. The maternal hormone balance appeared to be affected by smoking. Smoking affected maternal serum levels of hPL and hCG in pregnancies with a female fetus whereas maternal serum concentrations of oestriol and prolactin were affected in pregnancies with a male fetus. Significantly higher hCG levels were found in mothers who smoked and had a girl than in those who smoked and had a boy. On the basis of our results we feel that smoking mainly affects the placenta.