Preterm birth is defined as birth before 37 completed weeks of gestation .it occurs in
11.1%of birth globally affecting an estimated 14.9 million babies every year . It is
generally accepted that approximately 65%-70%of preterm births are spontaneous,40%-45% of
them due to spontaneous preterm labor and 25%-30%following preterm rupture of
membranes.preterm birth represents the single largest cause of morbidity and mortality for
newborn and is estimated for 29%of deaths in the first four weeks of life and also is
estimated for of major cause of morbidity for pregnant women .
Tocolytic agents include a wide range of drugs that can slow or suppress uterine contractions
. Tocolytic are considered advantages in spontaneous preterm labor to : (a) allow time for
the fetus to mature ,potentially avoiding deleterious effects of pre-maturity . (b)allow time
for antenatal corticosteroids to be administered and have clinical effect. (c) allow time for
intrauterine transfer to higher-care center where neonatal intensive care facilities are
available . the ideal Tocolytic agent should be effective , easy to administer , without
significant material ,fetal or neonatal side effects and permit time for antenatal
corticosteroids to be administered and take effect . a variety of Tocolytic treatments have
been used to inhibit uterine activity in women in spontaneous preterm labor , including
betamimetics , calcium channel blockers , magnesium sulfate , prostaglandin inhibitors and
oxytocin receptor antagonists however there is considerable global variation in types , doses
and regimens of tocolytic agents uses to manage preterm labor .
A comparison study between Ritodrine, magnesium sulfate and Nifedipine in terms of effect and
morbidity will be conducted.