ABSTRACT
Preterm labor is the comonest cause of perinatal death and neonatal morbidity. It occurs in 5-10% of all births. Attempts to suppress preterm labor by various tocolytic agents have been made in order to prevent these complications. Several drugs were used to achieve tocolysis with various side effects and varying usccess rates. Twenty pregnant patinets with excessive uterine activity at 26 - 37 weeks were studied. Ten of them were given ritodrine hydrochloride [yutopar] and the other ten patients were given magnesium sulphate. Six patients form both groups where the single agent caused serious side effects [ritodrine HCL] or failed to suppress uterine activity [magnessium sulphate], were given both agents simultaneously in modified dosage. Ritodrine HCL suppressed preterm labour in 8 patients [80%] without causing side effects while in the remaining 2 patients [20%] it had to be discontinued due to the intolerable side effects of chest compression, severe chest pain and dyspnea. MgSO[4] succeeded to suppress preterm labour in only 6 patients [60%] and failed in 4 patients [40%].In those 6 failures [2 from the ritodrine group and 4 from the MgSO[4] group] both agents were given simultaneously at a lower dose with successful tocolysis in 83.7% of cases but without complete elimination of the serious cardiovascular side effects of ritodrine. Neither agent caused fetal distress, only mild fetal tachycardia was observed in patients given ritodrine. Pregnancy has continued after suppression of preterm labour for 70.5 days in the ritodrine group, 56.8 days in the MgSO[4] group and 56.9 days in the patients given both together. This study showed that ritodrine HCL is more effective than MgSO[4] in suppressing preterm labour but may cause serious cardiovascular side effects. It is recommended that the two agents should not be used simultaneously and each agent should be used on its own and replaceed by the other agent in cases of failure to suppress preterm labour or development of serious side effects