Comparison of effects of labor epidural analgesia initiated in latent phase and active phase on parturients and neonates

Objective To compare the effects of labor epidural analgesia initiated in latent phase and active phase on parturients and neonates. Methods One hundred twenty nulliparous women at full term (single, head presentation, ASA Ⅰ or Ⅱ ) were randomly divided into 3 groups (n=40 each):control group(group C) ; PCEA initiated in latent phase group (cervical dilatation 0.5-3.0 cm) (group L) and PCEA initiated in active phase group (cervical dilatation＞3.0 cm) (group A). Epidural catheter was placed through L2,3 interspace. 0.1% ropivacaine with fentanyl 2 μg/ml was used for PCEA. A test dose of 5 ml was followed by a loading dose of 10 ml. PCEA device was programmed to allow a bolus of 6 ml with a 30 min lockout interval. The intensity of pain was measured with VAS (0=no pain, 10=worst pain) before analgesia, at 5, 10, 15 and 30 min after beginning of PCEA and cervical dilatation of 7-8 cm and 10 cm. Degree of motor block was assessed by lower extremity muscle strength (modified Bromage scale,0=no motor block, 3=inability to flex ankle joints).Plasma cortisol in maternal venous blood obtained before analgesia and at delivery of fetus and in umbilical cord blood and plasma ropivacaine concentrations in umbilical core blood were determined.The length of every stage, duration of analgesia,delivery mode, the amount of oxytocin used, maternal satisfaction, Apgar scores of the neonates and adverse effects were recorded. Results PCEA initiated in latent phase or active phase significantly reduced VAS score, the plasma cortisol level at delivery, the duration of 1st stage of labor, and the rate of cesarean section and increased the use of oxytocin in L and A groups as compared with group C, but there was no significant difference in the above variables between L and A groups. The duration of analgesia was shorter in group A than in group L. Conclusions Labor epidural analgesia initiated in latent phase or active phase can decrease the rate of cesarean section but does not prolong the duration of labor and is safe for the newborn. Key words: Analgesia, obstetrical;  Analgesia,epidural;  Labor, obstetric;  Pregnant women;  Fetus