Effect of cigarette smoking on plasmatic regulation of vascular prostacyclin in pregnancy and puerperium

Prostaglandins, particularly prostacyclin, participate in the control of fetal and maternal circulations. In the present study the effect of cigarette smoking on plasma prostacyclin-stimulating activity during late pregnancy and the puerperium (four to six months) and in the newborns was assessed. Plasma samples from 22 apparently healthy nonsmokers and 17 smokers (more than 15 cigarettes per day) were obtained twice during pregnancy and once after delivery. Plasma samples from nine infants born to smokers and seven infants born to nonsmokers were obtained 72 to 96 hours after birth. Plasma activity was evaluated by incubating the plasma samples with cultured rat aortic smooth muscle cells and measuring the prostacyclin released in the culture medium by specific radioimmunoassay of its stable metabolite, 6-keto-prostaglandin F1 alpha. In all of the women, plasma activity did not change significantly during pregnancy or after delivery. In smokers, plasma activity was always lower than in nonsmokers, but not significantly so. The plasma activity of infants born to smokers was significantly lower than that of infants born to nonsmokers.