Anesthesia for cesarean section requires special importance because it may affect both mother and the baby. To avoid maternal hypotension related to spinal anesthesia must be the primary objective during anesthesia. Even though many factors influence sensory nerve block for surgical anesthesia, local anesthetic dose is the main determinant. Another factor that influence the sensory nerve block is the obesity related to pregnancy. Due to the enlargement of epidural venous plexus related to pregnancy, the subarachnoid and epidural space reduces, so the local anesthetic requirement also reduces. Many investigators recommend lower dose of local anesthetic in obese patients due to reduced requirement There are many studies about dose regimens for cesarean anesthesia, but ideal dose have not been found. Investigators have designed this study to see the effects of conventional dose (10 mg bupivacaine) vs. low dose plus fentanyl (7,5 mg bupivacaine+25 mcg fentanyl) in obese and normal weight pregnant for cesarean section. The hypothesis was: the low dose regimen provides surgical anesthesia in obese patients while avoiding maternal hypotension.

Inclusion Criteria:

• Pregnant patients

Exclusion Criteria:

• Spinal anesthesia contraindications, thrombocytopenia, coagulation defects, cardiomyopathy, placenta previa, twin pregnancy, hypersensitivity to amide local anesthetics or fentanyl, infection at the injection site, neurologic disease.

Patients undergoing cesarean section under spinal anesthesia in obstetric clinic