• Amniotic fluid;
  • macrophage colony-stimulating factor;
  • normotensive pregnancies;
  • pregnancies that produced appropriate-for-gestational-age infants;
  • pregnancies that produced small-for-gestational-age infants


Macrophage colony-stimulating factor (M-CSF) promotes placental growth and maintenance. We evaluated whether amniotic fluid M-CSF levels were altered in normotensive pregnancies that produced small-for-gestational-age (SGA) infants arising from unknown factors.

Method of study

This study enrolled 68 Japanese women experiencing normotensive pregnancies with single fetuses. Of these pregnancies, 22 delivered SGA infants arising from unknown factors (SGA group); one delivered an SGA infant with intestinal obstruction. The other 45 were women who delivered appropriate-for-gestational-age (AGA) infants (AGA group). They were selected as controls. Amniotic fluid was collected and the M-CSF levels were compared between the two groups. The M-CSF level was determined by enzyme-linked immunosorbent assay method.


Amniotic fluid M-CSF concentrations were 6525 pg/mL (median) in the SGA group and 4790 pg/mL in the AGA group; the concentrations were significantly higher in the SGA group than in the AGA group. The M-CSF concentrations in the woman who delivered an SGA infant with intestinal obstruction showed very high values (24290 pg/mL).


We demonstrated a significant increase in amniotic fluid M-CSF levels in the SGA group. Excessive concentrations of M-CSF in amniotic fluid via amniotic membranes may be highly related to immunological abnormalities contributing to low birth weight of neonates.