The Tocolytic Efficacy of Nifedipine in the Management of Threatened and Advanced Preterm Labor: A Study on 444 Singleton Pregnant Women With Intact Membranes

Preterm birth is the main reason of perinatal morbidity and mortality. The main management method of this important problem is to prolong the pregnancy period and to use corticosteroids to prevent fetal pulmonary distress. The most widely studied tocolytic agents, ritodrin, salbutamol and terbutaline are all betamimetics, and they are shown to prolong birth labor till 7 days and do not have any effct on the fetal mortality. However, their maternal side-effects are inevitable and can be mortal. They cause tachycardia, hypotension and some biochemical disturbances. Furthermore, maternal death is possible due to pulmonary edema. These adrenergic agonists are the first line tocolytics, but calcium canal blockers are becoming more popular since they have less side effects and comparable efficacy.

Calcium canal blockers are nonspecific smooth muscle relaxants used in adult hypertension treatment. Their tocolytic effect depends on their inhibition of calcium ions into the myometrial cells. In vitro studies have shown that they have strong relaxant effects on human myometrium. In the present study, our aim is to investigate the effects of nifedipine in our clinic in a period between 2002 and 2005, when it was first used in our clinic as the sıngle tocolytic agent. Its success in preventing preterm labor and its complications in our earlier practice will be noted and this retrospective study will guide us in its current usage, dosages and side-effects.