20. Overview of results: Obstetrics.

Outcome	Total (95% CI)	Subgroup: blood salvage (collection time)			Subgroup: transfusion threshold
		Intraoperative	Postoperative	Both	No transfusion threshold	Liberal threshold (Hb > 80 g/L)	Restrictive threshold (Hb ≦ 80 g/L)
Risk of transfusion	POR 0.82 [0.38, 1.76] 1 RCT, N = 1349 ⨁⨁◯◯	POR 0.82 [0.38, 1.76] 1 RCT, N = 1349 ⨁⨁◯◯			POR 0.82 [0.38, 1.76] 1 RCT, N = 1349 ⨁⨁◯◯
Volume transfused (PPR)	MD ‐0.02 [‐0.08, 0.04] 1 RCT, N = 1349 ⨁⨁⨁⨁	MD ‐0.02 [‐0.08, 0.04] 1 RCT, N = 1349 ⨁⨁⨁⨁			MD ‐0.02 [‐0.08, 0.04] 1 RCT, N = 1349 ⨁⨁⨁⨁
Volume transfused (PPT)	MD ‐0.41 [‐2.26, 1.44] 1 RCT, N = 27 ⨁⨁◯◯	MD ‐0.41 [‐2.26, 1.44] 1 RCT, N = 27 ⨁⨁◯◯			MD ‐0.41 [‐2.26, 1.44] 1 RCT, N = 27 ⨁⨁◯◯
All‐cause mortality
Blood loss
Re‐operation
Infection
Wound complication
VTE/thrombosis
DVT
PE
MACE
MI
CVA/stroke
Hospital LOS

Bolded data highlights where there was a clear intervention effect.

"Volume" refers to mean transfusion volume; "transfusions" refers to number of people receiving an allogeneic transfusion

CI: confidence interval; CVA: cerebrovascular accident; DVT: deep vein thrombosis; Hb: haemoglobin; LOS: hospital length of stay; MACE: major adverse cardiovascular events; MD: mean difference; MI: myocardial infarction; N: number of people analysed; PE: pulmonary embolism; PJI: prosthetic joint infection; POR: Peto odds ratio; PPR: per person randomised; PPT: per person transfused; RCT: randomised controlled trial; RD: risk difference; RR: risk ratio; VTE: venous thromboembolism

⨁◯◯◯ = Very low certainty; ⨁⨁◯◯ = Low certainty; ⨁⨁⨁◯ = Moderate certainty; ⨁⨁⨁⨁ = High certainty