Background: Cigarette smoking during pregnancy is paradoxically associated with a reduced risk of developing preeclampsia. Both smoking and preeclampsia are associated with alterations in circulating angiogenic factors. The objective of this study was to investigate the relationship between cigarette smoking and the angiogenic factors soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) in pregnant women with and without preeclampsia.
Methods: Plasma sFlt-1, PlGF, and cotinine were measured using enzyme-linked immunosorbent assay in 125 women with uncomplicated pregnancies (controls) and 58 women with preeclampsia.
Results: In uncomplicated pregnancies, maternal sFlt-1 concentrations were lower in smokers compared to nonsmokers (779.6 (487.5-1,140.8) vs. 1,116.5 (793.6-1,905.2) pg/ml, P < 0.005). Preeclamptic women who smoked also demonstrated a trend toward lower concentrations of sFlt-1 compared to nonsmokers (3,423.0 (2,183.4-5,689.0) vs. 5,504.9 (3,418.0-6,361.3) pg/ml, P = 0.07). Maternal PlGF concentrations were higher in smokers with uncomplicated pregnancies (398.4 (165.2-621.7) vs. 191.4 (104.6-446.8) pg/ml); however, this was not a statistically significant difference (P = 0.07). PlGF concentrations were not different in preeclamptic smokers compared to nonsmokers. The sFlt/PlGF ratio was significantly lower in smokers with uncomplicated pregnancies, but not in smokers with preeclampsia compared to nonsmokers.
Conclusions: Cigarette smoking is associated with lower maternal sFlt-1 concentrations during pregnancy and preeclampsia. On the basis of these data, cigarette smoke exposure may decrease the risk of preeclampsia in part by moderating the anti-angiogenic phenotype observed in the syndrome.