The effect of combined tocolysis on in vitro uterine contractility in preterm labour

Purpose: Animal models have confirmed high efficiency of combined tocolytic treatment in preterm labour. In humans, the recommended doses of tocolytic drugs prolong pregnancy in threatened preterm labour. The aim of the study was to evaluate the inhibitory effect of dual combinations of atosiban, nifedipine and celecoxib on human myometrial strips contractility on the in vitro model of preterm labour. Material/methods: Two groups of patients who delivered by cesarean section were involved in the study: 36 patients who delivered preterm between the 24(th) and 34(th) week of pregnancy and 40 patients who delivered at term. Myometrial samples were obtained from the lower uterine segment during cesarean sections. Contractile activity was recorded with digital software for each drug combination: atosiban/nifedipine; atosiban/celecoxib, nifedipine/celecoxib. Tocolytic efficiency of the drug combinations was assessed using IC50 parameter - a molar drug concentration inhibiting 50% of contractility. Results: The atosiban/nifedipine combination has shown additive tocolytic effect on myometrial strips contractility in preterm and term patients. The other combinations: atosiban/celecoxib and nifedipine/celecoxib presented only antagonistic effects in both studied groups. Conclusions: The effect of the combined therapy on human myometrial contractility presented in the study could be a base for further in vivo clinical trials.