Objective

To evaluate maternal serum tumor necrosis factor-alpha (TNF alpha) levels in patients with preterm labor without clinical signs of chorioamnionitis and to compare these with levels in nonlaboring controls.

Study design

The study group consisted of 44 patients with a singleton pregnancy admitted to our department with the diagnosis of preterm labor between 26 and 36 weeks' gestation. The control group consisted of 25 healthy consecutive patients with a singleton pregnancy without preterm contractions who were seen for routine antenatal visits. Maternal serum TNF alpha was measured using a solid-phase, two-site chemiluminescent enzyme immunometric assay method, and levels were compared in patients with preterm labor and nonlaboring controls.

Results

The median maternal serum TNF alpha level for patients with preterm labor was 29.4 pg/mL (range, 12.3-173) as compared with 23 pg/mL (range, 11.9-62.7) in the control group (P=. 031). Among 44 patients with preterm labor, 14 (32%) delivered within one week of admission. The median maternal serum TNF alpha level was significantly higher in patients who delivered within one week than in those who delivered after one week and controls (71.3 pg/mL [range, 28-173]) versus 22 pg/mL (range, 12.3-86) versus 23 pg/mL (range, 11.9-62.7)(P<. 0001).

Conclusion

TNF alpha was elevated in patients with preterm labor, suggesting a role for maternal serum TNF alpha in its initiation.