Magnesium Sulfate (MgSO4) and Fetal Heart Rate (FHR) in Case of Prematurity

Type of study: prospective descriptive monocentric study Population: 2 groups: -Exposed group: pregnant patient between 24AW+0day and 32AW+0day receiving magnesium sulfate for fetal neuroprotection in the doubt of premature delivery * Control group: pregnant patient between 32AW+1day and 35AW+0day in the same context not requiring magnesium sulfate due to their gestationnal age. Criterion(s) of judgment: Appearance of a change in short-term variability after injection of magnesium sulfate in the exposed group compared to the control group. Schedule: Inclusion from February 20 to August 31, 2018 Expected results and prospects: The general impression during my semester at the Jeanne de Flandre maternity clinic in Lille was the variability improves after injection of the magnesium sulfate used in the premature infant as a neuroprotective. The investigators would like to proove that the use of magnesium sulfate as neuroprotective in premature fetuses would improve the fetal heart rate by increasing variability. In the literature there are numerous publications on the effects of magnesium sulfate used as tocolytic (higher doses) in the threats of premature labour, generally showing a variability and number accelerations decreases without increase the number of decelerations. Is this effect is the same as the doses used for fetal neuroprotection? Expected benefits of the research: Magnesium sulfate used on premature infants for fetal neuroprotection has an impact on fetal heart rate, including variability and number of accelerations.