Background and Aims Randomized trials show that the use of the PIEB reduce the frequency of the motor block, fewer manual boluses and provides greater maternal satisfaction compared to CEI.

The aim of study was to compare the dynamics of the sensory block of PIEB+PCEA to CEI+PCEA for maintenance labor analgesia.

Methods We studied 70 subjects. The level of the sensor block evaluated the «pin-prick» test. All parturients divided into 2 groups:

4 – loading dose of levobupivacaine 0.125% – 10.0 ml, then CEI (0.0625% – 15 ml/hour) + PCEA (0.0625% – 10.0 ml every 20’);

5 – loading dose of levobupivacaine 0.125% – 10.0 ml, then PIEB (0.0625% – 9.0 ml every 45 ‘) + PCEA (0.0625% – 10.0 ml every 10’).

Results The results indicate that in the PIEB group, the level of sensory block in patients was higher after 15 minutes the start of analgesia and remained so until the end of the observation period (median PIEB Th5 versus Th8 in the CEI group, (p <0,0004). When cervical dilation full (II stage), the intervals and distributions of the sensor block level in the CEI and PIEB groups completely diverge (p <0.00001). The median and peak frequency of the sensor block level in the CEI group are at Th9, while the same statistics in the PIEB group are Th6.

Conclusions PIEB + PCEA technique maintained a consistently high level of sensor block throughout the study compared to PCEA + CEI, which ensured effective analgesia in the first and second stages of labor.