Objective: The purpose of this study was to determine whether the increase in serum macrophage colony-stimulating factor (M-CSF) levels preceded the onset of preeclampsia.
Study design: We selected 146 women, of whom 36 were nonpregnant women participating in the preliminary study and 110 were normotensive pregnant women at risk for preeclampsia who were carrying single fetuses at about 18 weeks of gestation. The blood was collected and serum was stored at -20 degrees C until assay. Sixteen women had preeclampsia develop at a later stage of pregnancy (preeclamptics), whereas 89 women continued to have normotensive pregnancies until delivery. Thirty-five of the 89 women with normotensive pregnancy who were matched for age and parity were selected to form a control group (controls). Serum M-CSF levels were determined by the sandwich enzyme-linking immunosorbent assay method with use of three antibodies.
Results: Serum level of M-CSF was 1295 U/mL (median) in preeclamptics and 957 U/mL in controls. Serum M-CSF levels were significantly higher (P<.0001) in preeclamptics than in controls.
Conclusion: The increase in serum M-CSF levels markedly precedes the development of clinical manifestations of preeclampsia. Elevation of serum M-CSF supports M-CSF elevation in the placenta. This elevation at 18 weeks of gestation may be related to placental hypoxia, which is considered the cause of preeclampsia.