Comparing Fetal Cerebral Blood Flow Between Magnesium Sulfate & Calcium Channel Blockers in Patients With Preterm Labor; a Randomized Controlled Trial.

After internal review board approval from the obstetrics and gynecology department of Kasr Alainy hospital, 130 patients will be recruited in a randomized case control study. The patients will be recruited from the emergency admissions department, after fulfilling the recruitment criteria. In an independent case-control study the Sample size was calculated using an odds ratio of exposure to CP of 0.14 (95% CI 0.05-0.51) (Grether et.al, 1998), where the alpha level error was fixed at 0.5 and the power was set at 80%, the optimal sample size was calculated to be 65 patients in each arm.

Patients will be randomized on admission by nurse in labor ward into either one of two groups. Group A will receive MgSo4, while group B will receive Nifedipine ( Epilat 20mg ® EIPICO Egypt ). Randomization will be achieved through a computer generated randomization table. Recruitment will continue till 65 patients will be allocated to each group.

Patients in group A will receive 4 gm intravenous (I.V) MgSo4 loading dose over 30 mins & 1 gm/ hour maintenance dose for 24 hours, or till labor occurs ( whichever occurs first) , this does is given in accordance with Australian Research Centre for Health of Women and Babies, 2010, for using MgSo4 for neuroprotection against CP.

While patients in group B will receive Nifedipine ( Epilat 10mg ® EIPICO Egypt ), as there is no recommended dose for the use of nifedipine as neuroprotectant, the dose given in this study will be same as that used for tocolysis. Nifedipine wil be given in a loading dose of 40 mg in the 1st hour (10mg will be given every 15 min), then a maintenance dose of 60mg /24 hours, divided in 3 doses (Hösli et.al, 2014).

The ability of the MgSo4 as a neuro protectant is dependent on its cerebral vasodilating effects (Magee et.al,2011; Macdonald et.al, 2004), therefore we propose to measure the mean pulsility index (PI) and resistance index (PI) of the middle cerebral artery in the fetus twice, once before giving them the drug, and the other after 4 hours of starting the loading dose. All ultrasound and power doppler examinations will be carried out by the same investigator, using the Voluson 730 machine (GE Healthcare Austria GmbH, Seoul, Korea). Sample size calculation was done using Stats Direct statistical software version 2.7.2 for MS Windows, StatsDirect Ltd., Cheshire, UK.