Elevated levels of serum macrophage colony-stimulating factor in normotensive pregnancies complicated by intrauterine fetal growth restriction.

Objective: Macrophage colony-stimulating factor (M-CSF) is considered an essential cytokine for placental growth and maintenance. M-CSF also may regulate trophoblast invasion into the placental bed. The aim of the present study was to evaluate whether serum M-CSF levels were altered in normotensive pregnancies complicated by intrauterine growth restriction (IUGR) arising from unknown factors. Plasma thrombin-antithrombin complex (TAT) levels and the pulsatility index (PI) values also were measured.

Patients And Methods: This study enrolled 47 Japanese women experiencing normotensive pregnancies with single fetuses. Of these pregnancies, 20 were complicated by IUGR arising from unknown factors; these women later delivered small-for-gestational-age (SGA) infants. The other 27 women later delivered appropriate-for-gestational-age infants (controls). The women's ages and gestational ages did not differ significantly between the two groups. Maternal peripheral blood was collected, and the levels of serum M-CSF and plasma TAT were compared between two groups. The M-CSF level was determined by the sandwich enzyme-linked immunosorbent assay method and the TAT level by the enzyme immunoassay method. The PI value for the middle cerebral artery of the fetuses was calculated.

Results: Serum levels of M-CSF were significantly higher (p < 0.005) in pregnancies complicated by IUGR that produced SGA infants than in controls. Plasma levels of TAT also were significantly higher (p < 0.02) in pregnancies that produced SGA infants than in controls. The PI values were significantly lower (p < 0.05) in pregnancies that produced SGA infants than in controls.

Conclusions: This study demonstrated significant increases in serum M-CSF levels in women with normotensive pregnancies complicated by IUGR arising from unknown factors who later delivered SGA infants. To the best of our knowledge, this is the first such report. Elevated serum M-CSF levels may be related to placental hypoxia leading to pregnancies complicated by IUGR.