Intravenous administration of cocaine stimulates gravid baboon myometrium in the last third of gestation

Intravenous cocaine administration appears to increase uterine contractions in pregnant baboons. Seven pregnant baboons in their last trimester had a catheter placed in the femoral artery and vein and sensors sutured into the uterine muscle. A jacket arrangement allowed free mobility. Five days after surgery various dosages of cocaine were infused. Muscle activity increased over baseline at all dosage levels, i.e., 0.3 milligrams per kilogram of body weight (mg/kg), 0.5 mg/kg, and 1.0 mg/kg. The amount of activity increased as the dosage increased. This may be one mechanism for reducing uterine blood flow, a known effect of cocaine.