Oxidative Stress in Women Treated With Atosiban for Impending Preterm Birth

The initial dose of Atosiban (Tractocile, Ferring Pharmaceuticals A/S, Copenhagen, Denmark) will be give as a single intravenous bolus dose (6.75 mg in 0.9 ml isotonic sodium chloride solution). This will be follow immediately by intravenous infusion of 300 μg/min of Atosiban in 5% glucose for 3 hours, and then 100 μg/min for up to 48 hours. Venous blood samples from a forearm vein will take before and after 48 hours of continuous administration tocolytic therapy with Atosiban.