PROBLEM: The purpose of this study was to determine whether the serum macrophage-colony stimulating factor (M-CSF) level is associated with early pregnancy loss in unexplained recurrent spontaneous abortion (RSA) patients.
METHOD: We therefore compared preconceptional serum M-CSF levels between unexplained RSA patients and controls. The former comprised 44 bed-rest therapy patients and 43 intradermal immunization (IDI) patients receiving paternal lymphocyte therapy, who had experienced two and three or more consecutive first-trimester pregnancy losses, respectively. The controls were 46 healthy non-pregnant women. We also prospectively studied the association between M-CSF levels during pregnancy and adverse pregnancy outcomes. Sera from a total of 31 pregnant women, including 16 of the bed-rest therapy group and 15 of the IDI therapy group, were collected at the 4th, 6th, and 8th gestational weeks and were measured for M-CSF levels, using the enzyme-linked immunoadsorbent assay (ELISA) method established by Hanamura et al.
RESULTS: Serum M-CSF levels were significantly lower in the non-pregnant RSA patients (460.0 ± 185.6 U/ml; mean ± SD) than in the control group (726.5 ± 134.0 U/ml) and also were lower at the 8th, but not the 4th or 6th gestational week in those patients of both the bed-rest and IDI therapy groups whose outcome was pregnancy failure.
CONCLUSION: Thus a low level of serum M-CSF was found to be associated with unexplained recurrent pregnancy loss in both the preconceptional and conceptional phases. These results raise the possibility that M-CSF may play an important role in the maintenance of pregnancy and that it can be used as a parameter for determining individuals at risk.