The investigators study the efficacy of epidural sufentanil/ropivacaine for analgesia labor in primiparas so as to decrease perinatal complications of analgesia labor.

A prospective study of 120 full-term parturients receiving labor analgesia were randomly assigned into 2 groups: the 0.5Sufen group (N=60), the 0.25Sufen group (N=60).

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.