Purpose: This study was designed to evaluate neopterin levels and low Apgar scores in pregnancies with gestational diabetes mellitus (GDM) vs. normal control pregnancies. Methods: We carried out a cross-sectional study by enrolling 81 pregnant women with GDM and 38 pregnant women without GDM. Results: Maternal and cord blood neopterin levels were higher in women with GDM. There was a significant positive association between fasting blood glucose levels and maternal serum neopterin levels. The results of 50-g oral glucose challenge tests revealed a correlation between maternal and cord neopterin levels. Pregnancies complicated by GDM exhibited lower fetal Apgar scores than those of control subjects. The levels of cord blood neopterin were inversely correlated with an fetal Apgar score of 1 min in patients with GDM. Conclusions: Patients with GDM had higher maternal and cord blood neopterin levels, and the cord blood neopterin levels are inversely associated with lower Apgar scores in women with GDM. The neopterin levels might be potential predictors of low fetal Apgar scores in women with GDM.