In this study, the investigators aim to compare the effect of Nifedipine and MgSO4 therapies on Doppler parameters of the uterine, umbilical, middle cerebral arteries, and ductus venous in the first 48 hours of therapy in pregnancies with preterm labor threat and also compare perinatal outcomes after delivery between the groups.
Comparison of the effects of Nifedipine and MgSO4 therapies on maternal and fetal blood flow.