The effects of intrapartum magnesium sulfate therapy on fetal serum interleukin-1 beta, interleukin-6, and tumor necrosis factor-alpha at delivery: Arandomized, placebo-controlled trial

OBJECTIVE: Elevated levels of inflammatory cytokines in the fetus have been linked to neurologic morbidities in preterm neonates. Magnesium sulfate is currently being studied in clinical trials as a potential fetal neuroprote ctive agent. The purpose of this study was to determine whether intrapartum magnesium sulfate therapy has an effect on the umbilical venous concentrat ions of interleukin-1 beta, interleukin-6, and tumor necrosis factor-alpha at delivery. STUDY DESIGN: Women with singleton gestations > 32 weeks with no clinical i ndications for magnesium sulfate therapy (preeclampsia or tocolysis) and ei ther clinical chorioamnionitis or prolonged rupture of membranes were recru ited for the study. Consenting patients were randomly assigned, in a double -blinded fashion, to receive either magnesium sulfate (6-g load then 2 g/hr ) or matched volumes of lactated Ringer's solution until delivery. Fetal bl ood specimens were obtained by aspiration of the umbilical vein after cord clamping but before placental separation. Umbilical cytokine levels were me asured with a sensitive and specific immunoassay. RESULTS: Twenty-two patients were randomly assigned to groups and received either magnesium sulfate (n = 11) or placebo (n = 11). There were no differ ences in the demographic or clinical characteristics between groups. The um bilical venous ionized magnesium concentration was significantly higher in the magnesium sulfate group (2.32 +/- 0.27 mg/dL vs 1.23 +/- 0.15 mg/dL; P < .001). There were no statistically significant differences between groups with respect to umbilical levels of interleukin-1 beta (1.5 pg/mL [1.5-58] vs 1.5 pg/mL [1.5-10]; P = .5); interleukin-6 (8.5 pg/mL [1-1000] vs 11.2 pg/mL [1-113]; P = .9); or tumor necrosis factor-a (16 pg/mL [7.6-20.3] vs 16.6 pg/mL [8.3-22.2]; P = .5). CONCLUSION: In this pilot study the intrapartum administration of magnesium sulfate does not appear to affect the concentration of inflammatory cytoki nes in fetal blood at delivery.