Effect of Sufentanil and Ropivacaine

Inclusion Criteria:

1. Patients had regular prenatal examinations at the outpatient clinic;
2. They were between 25 to 35 years of age)
3. They had a gestational age ≥37 weeks and < 42 weeks;
4. They had an estimated fetal weight ≥ 2,500 g and < 4,200 g.

Exclusion Criteria:

• a history of spinal surgery,
• platelet count <100×109 /L ,
• coagulation disorder,
• sensorimotor disorder of lower extremity,
• leg pain,
• puncture point infection,
• heart disease history,
• pulmonary disease,
• liver and renal function disorder and
• a history of neuropsychiatry drugs.