This study compares the efficacy of two different doses of intravenous (IV) granisetron on the prevention of postspinal shivering during cesarean section, in comparison with placebo.

The study will includes four groups as follows:

1. Granisetron1 group: women will receive 1mg IV granisetron
2. Granisetron 0.7 group: women will receive 0.7 mg IV granisetron and
3. Control group: women will receive 2 ml of 0.9% sodium chloride. Throughout the study period,shivering scores, core temperature, sensory level and motor block will be recorded, heart rate will be measured continuously using an electrocardiogram; blood pressure will be determined. If heart rate decreases by more than 20% of the baseline atropin will be received and if blood pressure decreases 20% of the baseline ephedrine will be received.

Also, Apgar score at one minute and five minutes will be recorded. At the end patient satisfaction will be assessed using Verbal Numeric Scoring system Side effects (bradycardia, hypotension, hypothermia, nausea and vomiting, pruritus etc ) will be recorded perioperatively in the operating room and postanesthetic care unit.

Inclusion Criteria:

• pregnant women at term,
• ASA status I or II (American Society of Anesthesiologists) physical status class I-II,
• low-risk cesarean section,
• Scheduled for the spinal anesthesia

Exclusion Criteria:

• Pregnant women in labor
• Patients who have the body temperature over 37.3 or less than 37 celsius degree
• Known allergies to the study drugs
• Contraindication to spinal anesthesia