Objectives: To evaluate the tocolytic effectiveness and safety of atosiban in comparison to the ß-agonist ritodrine for prolongation of pregnancy time.
Patients & Methods: The study included 250 pregnant women presented with a picture of preterm labor and were randomly allocated into 2 equal groups according to the tocolytic infusion: Atosiban (Tractocile) infusion in Group A and Ritodrine hydrochloride (Yutopar) infusion in Group B. Throughout the time of infusion maternal blood pressure and pulse rate and fetal heart rate were monitored. Primary outcome of the study was to define the 48-hr and 7-day delivery rates, percentage of women had prolonged pregnancy and women delivered during 48-hr after initiation of therapy or still had contractions after 48 hours were considered as intervention failure. Uterine contractions reappearance after stoppage was considered as relapse rate and treatment was repeated. Secondary outcome of the study was the frequency of side effects.
Results: Throughout the 1st 24-hr, 169 women responded to tocolytic therapy; 95 in group A and 74 in group B, with significantly higher difference in favor of group A. However, by the end of the 1st 24-hr, 68 of responders relapsed with significantly higher relapse rate in group B. By the end of 48 hours of continued tocolytic therapy, 40 women; 15 in group A and 25 in group B, failed to respond with non-significantly reduced failure rate in group A. By the end of one-week, 97 women give birth; 42 in group A and 55 in group B, while 113 women; 68 in group A and 45 women in group B continued their pregnancy with significant difference in favor of group A. The cumulative failure rate of tocolytic therapy was significantly lower in group A (45.6%) compared to group B (56%). There was significantly higher frequency of tachycardia, palpitation, dyspnea and tremors in group B compared to group A. The only side effect of atosiban that occurred with high frequency was nausea and vomiting but with significantly lower rate compared to group B.
Conclusion: Tocolysis using atosiban infusion effectively allowed prolongation of pregnancy by 61.8% with minimal maternal and fetal side effects and considering its cost versus effectiveness and safety documented its use as first line of management for preterm labor. |
