Palomaki 2005a.

Methods	Randomised.
Participants	397 women with normal pregnancy and normal latent phase of labour age 18‐40 years, singleton, cephalic presentation, at 37‐42 weeks' gestation, normal cardiotocogram before PCB, ruptured membranes, cervical dilatation 3‐7 cm, no fetopelvic disproportion, no chronic maternal illnesses.
Interventions	PCB was administered with Kobac needle at the 3, 4, 8, 9 o'clock positions in the lateral fornix of the vagina at the depth of 3‐4 mm.
Outcomes	The intrauterine pressure, Apgar score, cord artery acid‐base balance, clinical outcome, analgesic effect of the block measured with visual analogue scale, median time from PCB to delivery, the type of delivery (spontaneous, vacuum extraction, caesarean section), admission to neonatal intensive care unit (NICU).
Notes	Non‐randomised pilot study to characterise the use of levobupivacaine in PCB, which included 40 women, was initially undertaken. Racemic bupivacaine was compared to levobupivacaine.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated randomisation.
Allocation concealment (selection bias)	Unclear risk	Not described.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Blinded.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Blinded.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Complete data.
Selective reporting (reporting bias)	Low risk	None identified.
Other bias	Low risk	No other bias were identified.