Introduction:

Preterm labor is one of the commonest clinical events where traditional pregnancy can turn into a high risk situation for the mother as well as the fetus. Magnesium sulfate (MgSO4), which is a calcium antagonist, has been used for over 30 years as short-term treatment (less than 48 h) for acute preterm labor. It acts by inhibiting voltage independent calcium channels in the myometrial cell surface. Extracellular magnesium suppresses calcium influx across cell membranes, whereas intracellular magnesium competes with calcium, there by inhibiting myosin light-chain kinase activity.

Aim of the Work:
The aim of the study was to evaluate the effect of magnesium sulfate administration on cerebroplacentalratio (CPR) assessed by Doppler ultrasound incases of threatened preterm labor.

Patients and Methods:
The study included one hundred ten pregnant women. All patients (n=110) underwent complete history taking, clinical examination, ultrasound examination for fetal biometry ,mean gestational age and color Doppler examination.