preeclampsia is defined as increase in systolic blood pressure 140 mmhg or diastolic 90 mmhg and proteinuria 300 mg protein/24 hours urine and starts after 20 weeks of pregnancy .
eclampsia is the condition in which generalized seizure occur in the absence of other neurologic defects .
preeclampsia and eclampsia are among the common causes of death and disability in pregnant women and are associated with increased vascular resistance and decreased uteroplacental perfusion .
it is characterized by vascular contraction , lesions in the placenta and umbilical arteries , high blood pressure , proteinuria , and seizure .
maternal complications include acute renal failure , liver damage , intracerebral hemorrhage , pulmonary edema , and death .
fetus complications are preterm birth or intrauterine growth restriction.[35 ] magnesium sulfate ( mgso4 ) is used for the treatment of severe preeclampsia and can help prevent serious complications .
effect of mgso4 on cerebral vessels are still controversial and it is unclear whether it reduces cerebrovascular vasospasm .
studies in this area are still ongoing.[811 ] the mechanism of action may include changes in vascular permeability and reduction of edema .
it seems to have no adverse effects on the fetus , but in response to mgso4 injection , fetal brain perfusion may also alter . in pregnancy , usually umbilical artery is tested by doppler ultrasound but some recent studies also test maternal and fetal middle cerebral arteries ( mca).[1417 ] in one study , the reference value of resistive index ( ri ) and pulsatility index ( pi ) have been investigated in iranian patients .
the ratio of middle cerebral artery / umbilical artery ( c / u ratio ) can be a good indicator of fetal prognosis and fetal well - being.[1620 ] doppler ultrasound is a useful tool for studying pathophysiological mechanisms that can affect the fetal hemodynamic status .
assessing the changes in the arteries with doppler ultrasound can show the adaptation of fetus to the situation .
investigating the mechanism of action of mgso4 on the fetus is one of the important issues in this disease .
the purpose of this study is to evaluate the effect of mgso4 in severe preeclampsia on fetal middle cerebral artery and umbilical artery using doppler parameters .
prior to the intervention , doppler ultrasound was used to evaluate the fetal middle cerebral and umbilical arteries of the patients .
patients with severe preeclampsia who attended imam reza hospital , kermanshah iran during the period 2011 - 2012 were included in the study .
inclusion criteria were : age in the range of 20 - 35 years , first pregnancy , gestational age above 28 weeks , systolic blood pressure 140 mmhg , and diastolic pressure 90 mmhg with the proteinuria of at least 300 mg in 24 hour urine or having urinary protein level  + 2 , and epigastric pain .
exclusion criteria were : any type of systemic disease ( e.g. , diabetes , hypertension , and autoimmune disorders ) , history of taking opium , smoking , twin pregnancy , and history of taking specific drugs . during the study period 21
the goal of the study and the method were described to all patients and written consent form was taken prior to the initiation of study .
after admission of the patient in a room that had cardiopulmonary resuscitation ( cpr ) facilities , a radiologist recorded the color doppler ultrasound of fetal umbilical and mca , using a siemens ultrasound device ( germany ) , model g40 , with a deep probe of 3/5 - 5 mhz .
the mean ri and pi of mca from the proximal part of two mca arteries ( left and right ) and the c / u ratio ( middle cerebral artery ri / umbilical artery ri ) were evaluated .
ri = peak systolic velocity - end diastolic velocity / peak systolic velocity pi = peak systolic velocity - end diastolic velocity / mean velocity after initial assessment , a gynecologist injected the primary and maintenance dose of mgso4 .
the primary dose had 14 g of mgso4 of which 4 g in the form of a 20% solution was injected intravenously for at least 4 min and then immediately 10 g of mgso4 in the form of 50% solution was injected muscularly .
twenty minutes after intravenous injection ( 4 g ) , doppler ultrasound was again performed to measure blood flow in fetal mca and umbilical arteries .
chicago , il , usa ) . kolmogrov - smirnov test was used to prove the normal distribution of variables and all variables had normal distribution . then the before and after intervention values were compared by paired t - test .
in the 21 patients studied , average ri - umbilical before and after the intervention were 0.72 ( 0.1 ) and 0.62 ( 0.09 ) , respectively , which showed a statistically significant decrease ( p < 0.001 ) .
the before and after pi - umbilical values were 1.35 ( 0.47 ) and 1.28 ( 0.49 ) , respectively , which was not a significant change ( p = 0.1 ) .
in addition , the average before and after ri - mca were 0.71 ( 0.16 ) and 0.71 ( 0.11 ) , respectively , and this particular index did not show any significant change ( p = 0.96 ) .
but , a statistically significant decrease ( p = 0.001 ) was observed in the average amount of before pi - mca 1.63 ( 0.84 ) and the after value 1.47 ( 0.69 ) . according to calculations , the before c
/ u ratio value was 1 ( 0.26 ) and the after value was 1.17 ( 0.29 ) , which showed a statistically significant increase ( p < 0.001 ) [ figure 1 ] .
the power of the test to compare before and after pi - umbilical values was calculated as 61.6% and 33.3% for ri - mca .
comparison of resistivity index ( ri ) and pulsatility index ( pi ) of umbilical and middle cerebral artery and c / u ratio before and after 20 min of administering magnesium sulfate ( mgso4 ) injection .
this study investigated the effect of administration of mgso4 in severe preeclampsia cases on fetal umbilical and mca blood flow .
based on the results of this study , the injection of mgso4 could significantly decrease the ri - umbilical , pi - mca , and increase c / u ratio .
fetal distress caused by hypoxia is one of the effects of preeclampsia on the fetus .
inadequate placental perfusion can cause fetal reduction of oxygen supply , and thus lead to fetal distress .
several studies have shown the medical effects of mgso4 in treating patients with preeclampsia and eclampsia .
souza et al , assessed fetal mca and umbilical artery doppler parameters and measured these parameters 20 min after injection of mgso4 .
they showed that umbilical and mca ri and pi values are significantly reduced . while in our study these parameters showed no significant change .
in addition , another study showed the reduction of pi in the fetal umbilical artery and mca due to the injection of mgso4 . in dasgupta 's study , when compared with control group , the umbilical artery pi value decreased , but the fetal mca - pi did not change significantly . in another study ,
the impaired perfusion in fetal mca can be associated with hypoxia and fetal complications . in our study , after injection of mgso4 , c / u ratio had a significant increase , which shows that the fetal blood supply had improved .
various studies confirmed the efficacy of doppler ultrasound examination for assessing the vascular status of the fetus and have introduced the c / u ratio as a parameter in assessing fetal blood supply .
the c / u ratio shows both inadequate fetal circulation and changes and adaptations in the artery .
hence , this drug ( mgso4 ) can cause vasodilatation in the fetal umbilical artery .
the fetal mca resistance increases in normal pregnancy slightly and the increase is more substantial in preeclampsia and eclampsia .
the administration of mgso4 , therefore , can have beneficial effects on the fetus and can increase perfusion .
c / u ratio is a good indicator for assessing the growth and prognosis of the fetus , while the fetal mca alone does not have the same value .
however , due to the special status of patients with severe preeclampsia , there are inevitable limitations in the design of this study and similar studies .
the small sample size was another limitation , which reduced the test power of pi - umbilical and ri - mca to less than 80% .
the lack of significant statistical differences in these two indicators might result from the small sample size of patients .
results of our study and studies of others indicate more extensive studies with larger patient numbers are required to be conducted and if possible a meta - analysis of the results of all existing studies to confirm conclusions about the effects of mgso4 on fetal blood flow is also essential .
infusion of mgso4 significantly decreases the fetal ri - umbilical and pi - mca and increases c / u ratio indices obtained with color doppler ultrasound evaluations .
 objective : to assess the effect of injecting magnesium sulfate on doppler parameters of fetal umbilical and middle cerebral arteries ( mca ) in women with severe preeclampsia.materials and methods : a total of 21 patients with severe preeclampsia admitted to imam reza hospital , kermanshah ( iran ) , were evaluated . before and after administration of magnesium sulfate 
 , doppler ultrasound scan was carried out to measure fetal middle cerebral artery and umbilical artery blood flow . paired t - test was used for statistical analysis.results:after injection of magnesium sulfate , the mean resistivity index ( ri)-umbilical , and pulsatility index ( pi)-cerebral showed a statistically significant reduction ( p < 0.001 ) . 
 the cerebroumbilical c / u ratio increased after the intervention ( p < 0.001 ) . 
 the pi - umbilical ( p = 0.1 ) and pre- and post - ri - cerebral ( p = 0.96 ) did not have statistically significant changes.conclusions:infusion of magnesium sulfate significantly decreases the flow in the fetus ri - umbilical and pi - mca , and it increases c / u ratio indices in color doppler ultrasound . 
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
CONCLUSIONS