الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Spontaneous preterm labor (SPTL) and preterm birth (PTB), is the single most important cause of perinatal mortality and morbidity in high income countries despite the enormous efforts over the past several decades.
Preterm labor is defined as regular, painful, frequent uterine contractions causing a progressive effacement and dilatation of the cervix occurring before 37 completed weeks of gestation.
In order to deal with preterm labor properly, we should understand well the complex mechanisms surrounding preterm birth.
The etiology of preterm labor is not single; it is likely to be multifactorial, with genetic, infectious, nutritional, behavioral, and other environmental contributors. Infection is implicated as a significant and major cause accounting about 40% of all cases of SPTL and PTB.
Large number of problems may occur in preterm infants as a consequence of being delivered too early. Bacterial infections are the major cause of mortality and morbidity in preterm infants However; two problems are the most significant causes of neonatal mortality and morbidity in the preterm infants which are neonatal respiratory distress syndrome (RDS) and intraventricular hemorrhage (IVH).
Numerous methods have been implicated in order to predict preterm labor including scoring systems, uterine activity monitors, cervical ultrasound and several biochemical markers. However, all those methods are still poorly sensitive.
There are many tocolytic drugs used to deal with preterm labor; however the real efficacy of those drugs is still debatable. Also there are many maternal complications occurred from the use of tocolytic drugs and should not be underestimated.
Tocolytics are drugs used to suppress uterine contractions. The most widely tested tocolytics are betamimetics. Although they have been shown to delay delivery, betamimetics have not been shown to improve perinatal outcome, and they have a high frequency of unpleasant and even fatal maternal side effects. This was the main cause in the growing interest to search for other more effective drugs with fewer side effects.
Nifedipine is a calcium channel blocker drug. It acts by reducing the intracellular entrance of calcium through the slow channel (or L type) producing an inhibition of contractile activity of non pregnant, pregnant and postpartum myometrium.