Inclusion Criteria:  Anesthesiologists risk score (ASA) I-II risk status Singleton pregnancy aged Between 18-40 years  Exclusion Criteria:  Pregnant women with contraindications for spinal anesthesia; Placental anomaly; Hypertension Cardiac disease Vascular disease Hepatic disease Renal disease Hemodynamic instability Spinal deformity; Severe mental retardation Weight < 50 kg or >110 kg; height < 140 cm or > 180 cm Metabolic and Acid-base balance disorders Emergency patients