Summary of findings 3. Local or regional anaesthesia for the prevention of chronic pain after caesarean section.

Should local or regional anaesthesia be used for the prevention of chronic pain after caesarean section
Patient or population: women after caesarean section Settings: maternity and university hospitals in South and North America, Egypt and Europe Intervention: local or regional anaesthesia Comparison: conventional pain control
Outcomes	Illustrative comparative risks* (95% CI)		Relative effect (95% CI)	No of participants (studies)	Quality of the evidence (GRADE)	Comments
	Assumed risk	Corresponding risk
	Control	Local or regional anaesthesia
Persistent pain 3 to 8 months after caesarean section (We defined persistent postsurgical pain as new pain that did not exist before the operation, measured using differences in scores based on validated pain scales; patient interview between 3 to 8 months after surgery.)	Study population		OR 0.46 (0.28 to 0.78)	551 participants (4 studies1)	⊕⊕⊕⊝ moderate2,3	Event rates of persistent pain after caesarean section are reported around 10%. The number of women needed to be treated for one woman to benefit from regional anaesthesia after caesarean section was 19.
	179 per 1000	91 per 1000 (58 to 145)
	Low
	50 per 1000	24 per 1000 (15 to 39)
	Moderate
	100 per 1000	49 per 1000 (30 to 80)
Adverse effects of local or regional anaesthesia ‐ not reported	See comment	See comment	Not estimable	‐	See comment	Adverse effects of local or regional anaesthesia after caesarean section were not systematically reported and due to their low frequency are better investigated in registries.
*The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: confidence interval; OR: odds ratio
GRADE Working Group grades of evidence High quality: we are very confident that the true effect lies close to that of the estimate of the effect. Moderate quality: we are moderately confident in the effect estimate; the true effect is likely to be close to the estimate of effect, but there is a possibility that it is substantially different. Low quality: we are moderately confident in the effect estimate; the true effect is likely to be close to the estimate of effect, but there is a possibility that it is substantially different. Very low quality: we have very little confidence in the effect estimate; the true effect is likely to be substantially different from the estimate of effect.

¹The results are based on only four, mostly smaller studies. Meta‐analysis results based on small numbers tend to overestimate the effects.
 ²The methodological quality of the larger trial was good, but only intermediate for the remaining studies.
 ³We downgraded quality of evidence by one level, because of the above noted two concerns, and because the pooled effect estimate is mainly driven by one larger study (Shahin 2010).