Maternal serum granulocyte colony-stimulating factor levels and spontaneous preterm birth

Preterm birth (PTB) remains a cause of substantial morbidity with an elusive etiology. Previous studies suggested an association of PTB with elevated serum levels of granulocyte colony-stimulating factor (G-CSF) at 28 weeks gestation. G-CSF, a hematopoietic cytokine, mediates the increase in leukocytes in pregnancy and may play a role in placentation. We evaluated the association between maternal serum G-CSF in the first and second trimesters and PTB.

Serum samples collected for the Collaborative Perinatal Project (CPP) from women with normal pregnancy (n = 394) and PTB (n = 31), defined as delivery before 37 weeks gestation, were used to assess G-CSF levels. Linear regression was used to evaluate the relation of G-CSF with gestational age (GA) at birth. Logistic regression, conditional on GA at sample provision, was used to model the association between G-CSF and PTB.

G-CSF was significantly associated with gestational age at birth (p = 0.02). In conditional logistic regression models, G-CSF was significantly associated with PTB, with an adjusted odds ratio (AOR) of 1.52 (95% confidence interval [CI] 1.07, 2.16) per standard deviation (SD) increase.

Acute effects of G-CSF on PTB have been suggested. In our study we observed an association of higher serum G-CSF levels early in the second trimester with PTB, suggesting PTB as the culmination process beginning early in, if not before, pregnancy.