Physiological distribution of placental growth factor and soluble Flt‐1 in early pregnancy

OBJECTIVE: To examine the distribution of placental growth factor (PlGF), vascular endothelial growth factor (VEGF) and soluble VEGF receptor-1 (sFlt-1) in maternal and embryonic fluid compartments in early pregnancy. METHOD: The concentrations of PlGF, VEGF and sFlt-1 were measured in coelomic fluid and maternal serum from 16 singleton pregnancies at 7.0-9.3 weeks. In six cases, amniotic fluid was also examined. RESULTS: The median concentration of PlGF was 14.1 (range 8.9-27.6) pg/mL in maternal serum, 13.9 (range 9.5-31.4) pg/mL in coelomic fluid and 8.9 (range 3.9-15.3) pg/mL in amniotic fluid. The concentration of PlGF increased between 7.0 and 9.3 weeks in maternal serum (p = 0.001) and decreased in coelomic and amniotic fluid (p = 0.001). The median concentration of sFlt-1 was 8561 (range 6724-10 673) pg/mL in coelomic fluid, 523 (range 244-986) pg/mL in maternal serum, 30 (range 12-83) pg/mL in amniotic fluid (p = 0.0001), and it did not change significantly with gestation. VEGF was undetectable in most of the samples, and therefore, no further analysis was performed. CONCLUSION: PlGF and sFlt-1 are present in the maternal and fetal fluid compartments in very early pregnancy, and their distribution is consistent with their site of production and the local conditions of transport.