Cocaine's effect on plasma oxytocin concentrations in the baboon during late pregnancy

OBJECTIVE: The hypothesis for this investigation was that intravenous cocaine would result in an elevation of maternal plasma oxytocin levels in the baboon during late pregnancy. STUDY DESIGN: Five gravid chronically instrumented baboons had timed arterial blood samples obtained before and after an intravenous bolus cocaine infusion at least 5 days after surgery. Plasma oxytocin concentrations were measured by specific radioimmunoassays, and baseline samples were compared with postcocaine samples. RESULTS: The plasma oxytocin concentrations were significantly elevated at all sampling times after the 1.0 mg/kg cocaine dose (p < 0.05). CONCLUSION: The increased oxytocin concentrations after cocaine use may be responsible for the increased incidence of preterm labor.