Intravenous administration of ritodrine for tocolysis has been associated with maternal cardiovascular and metabolic changes. Studies with other tocolytic agents, such as isoxsuprine, have shown an increased neonatal morbidity among infants born soon after failure of such therapy. We examined the potential side effects of maternal intravenous ritodrine therapy in 58 neonates born within 12 h following discontinuation of maternal medication. 'Low dextrostix' was significantly greater in the ritodrine exposed neonates (p less than 0.05) than in the controls. It occurred within a mean 1.0 +/- 0.5 h following birth. The mean 1 min and 5 min Apgar scores, neonatal pH, bicarbonate levels, hypotension and neonatal mortality were comparable in the ritodrine-exposed and control groups of neonates. The occurrence of any of the neonatal morbidity variables, including 'low dextrostix' was not related either to the total dose of ritodrine used or to the interval between drug discontinuation and delivery. Administration of ritodrine by the standard protocol to stop preterm labor is not associated with any significant increase in neonatal morbidity.