Low Maternal but Normal Fetal Prolactin Levels in Cigarette Smoking Pregnant Women

In the 36th week of pregnancy, levels of serum prolactin (PRL) (p <0.01) and estriol (p <0.05) were significantly lower in 101 consecutive women smoking 10 cigarettes or more per day, compared with a control group of 104 non-smoking pregnant women. Cord serum PRL was not related to maternal smoking habits, whereas estriol was significantly (p <0.05) lower in the infants of smokers, compared with the control group. The lower PRL levels in cigarette-smoking pregnant women may be due either to a direct effect of nicotine or secondary to lower estrogen levels, and the finding may be of clinical importance in relation to lactation.