Nesheim 1983.

Methods	Randomised.
Participants	115 women in labour at 4‐6 cm cervical dilatation.
Interventions	PCB was administered with Kobac needle at the 3, 4.30, 7.30, 9 o'clock positions. Group 1 (n = 43) ‐ 0.25% 20 mL bupivacaine. Group 2 (n = 22) ‐ 0.25% 20 mL bupivacaine with adrenaline 1:400,000. Group 3 (n = 28) ‐ 2% 20 mL chloroprocaine. Group 4 (n = 22) ‐ 2% 20 mL chloroprocaine with adrenaline 1:400,000. All blocks were given by either of 2 experienced obstetricians.
Outcomes	Pain relief on 10 cm visual analogue scale ‐ patient was asked a few minutes after she received the block to indicate the degree of pain she had before and after receiving the block. Duration of the block, time from PCB to fully dilatation, use of oxytocin, birthweight, Apgar score and method of delivery.
Notes	No outcomes assessed in our review were reported in this study.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomisation was done by tossing a coin twice, e.g. the first toss determined which anaesthetic, the second toss whether adrenalin should be used.
Allocation concealment (selection bias)	Unclear risk	Not described.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Not blinded.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Not blinded.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Complete data.
Selective reporting (reporting bias)	High risk	The authors reported Apgar score below 9 (not conventional 7) at 5 minutes, which is most likely underreporting of negative effect of intervention.
Other bias	Low risk	No other bias identified.