Neonatal metabolic effects of oral ritodrine hydrochloride administration.

Abstract

Neonatal hypoglycemia and hyperinsulinemia have been reported following maternal ritodrine administration, but no prospective controlled study of the neonatal metabolic and cardiovascular effects of maternal ritodrine is available. We conducted a double-blind prospective study in 35 patients with preterm labor and/or ruptured membranes. Patients in premature labor received ritodrine (max dose, 350 mcg/min) or a placebo intravenously for 12 hours, and then orally (20 mg every 4 hours) until labor ensued. Patients with ruptured membranes received only oral therapy. Only patients who were maintained on oral therapy for a minimum of 12 hours and who were within 6 hours of their last dose of oral therapy were included in the analysis. Glucose and insulin values in cord blood at 6 and 12 hours of age were not significantly different between the ritodrine and placebo groups. There were no hypoglycemic infants in the ritodrine group. Mean systolic and diastolic blood pressure, heart rate and blood volume were similar for ritodrine and control infants. Although premature infants are at high risk for hypoglycemia it appears from this study that chronic oral ritodrine therapy does not significantly affect neonatal glucose homeostasis.