Table 2 Methods of blood loss collection and calculation

Ali Movafegh [15]

Blood loss was collected through a suction container, gauze pads and operation sheets

The quantity of blood loss (mL) = (weight of used materials—weight of materials prior to used)/1.05 + (the volume included in the suction container after placental delivery)

H. Abdel-Aleem [16]

Blood loss was collected through a suction container, towels during operation, and through plastic drape after operation

The quantity of intra-operative blood loss (mL) = (weight of wet towels -weight of towels prior to used) × 0.9 + (the volume included in the suction container after placental delivery). The quantity of post-operative blood loss (mL) = weight of used drapes—weight of drapes prior to used) × 0.9

Mehmet B. Sentu ̈rk [17]

Blood loss was collected through operation pads and tampons (with 1 g sensitive scale)

The quantity of blood loss (mL) = (weight of used materials—weight of materials prior to used)/1.05

Anuradha Ghosh [18]

Blood loss was collected through a suction container, operation sheets, gauze pieces and mops (1 g is equivalent to 1 mL)

The quantity of intra-operative blood loss (mL) = (weight of used materials—weight of materials prior to used) + (the volume of blood sucked in suction bottle). The quantity of post-operative blood loss (mL) = weight of used pads—weight of pads prior to used

Haitham Torky [19]

Blood loss was collected through towels

The quantity of blood loss (mL) = weight of used materials—weight of materials prior to used

Abd El-Naser Abd El-Gaber [20]

Blood loss was collected through a suction container, towels, and pads

The quantity of intra-operative blood loss (mL) = (weight of used towels—weight of towels prior to used) + (the volume sucked in the suction bottle after placental delivery). The quantity of post-operative blood loss (mL) = weight of used pads—weight of pads prior to used

Forozan Milani [21]

Blood loss was collected through a suction container, gauzes, sterile drapes, and pads

The quantity of intra-operative blood loss (mL) = (weight of used materials—weight of materials prior to used) + (the volume of blood sucked in suction bottle). The quantity of post-operative blood loss (mL) = weight of used pads—weight of pads prior to used

Zahra Naeiji [22]

Blood loss was collected through a suction container, drapes, mops, sponges, pads, and operation table perineal sheet

The quantity of intra-operative blood loss (mL) = (weight of used materials—weight of materials prior to surgery) + (the volume sucked in the suction bottle after placental delivery). The quantity of post-operative blood loss (mL) = weight of used pads—weight of pads prior to used

Amr H. Yehia [23]

Blood loss was collected through a suction container, towels, and pads. Soaked towel = 150 mL. while semi-soaked towel = 75 mL. soaked pads = 50 mL

The quantity of intra-operative blood loss (mL) = (weight of used materials—weight of materials prior to used) + (the volume of blood sucked in suction bottle). The quantity of post-operative blood loss (mL) = weight of used materials—weight of materials prior to used

Cohort Studies

Upasana Goswami [24]

Blood loss was collected through a suction container, and soaked material such as sponges, mops, pads, and drapes were weighed

The quantity of intra-operative blood loss (mL) = (weight of the abdominal swabs and drapes—weight of materials prior to surgery) + (the volume in the suction bottle after placental delivery)

Ming-ying Gai [25]

Blood loss was collected through a suction container, and soaked gauze, pads and a specially designed operation table sheet were weighed

The quantity of blood loss (mL) = (weight of used materials + unused materials—weight of all materials prior to surgery)/1.05 + (the volume included in the suction container after placental delivery)

Tullika Singh [26]

Blood loss was collected through a suction container, sponges, and pads

The quantity of intra-operative blood loss (mL) = (weight of used materials—weight of materials prior to surgery) + (the volume of blood sucked in suction bottle). The quantity of post-operative blood loss (mL) = weight of used pads—weight of pads prior to used

A. V. Chandak [27]

Blood loss was collected through a suction container, pads

The quantity of intra-operative blood loss (mL) = (weight of used materials—weight of materials prior to surgery) + (the volume of blood sucked in suction bottle). The quantity of post-operative blood loss (mL) = weight of used pads—weight of pads prior to used

Leila Sekhavat [28]

Blood loss was measured by weighting-soaked sheet, via a specially designed operating sheet and an electronic scale to weigh all the material (with a 1 g deviation range)

The quantity of intra-operative blood loss (mL) = (weight of used materials–weight of materials prior to surgery)/1.05. The quantity of post-operative blood loss (mL) = weight of used sheets—weight of sheets prior to used

Irene Ray [29]

Blood loss was collected through a suction container, sheets, mops, and pads

The quantity of intra-operative blood loss (mL) = (weight of used materials—weight of materials prior to used)/1.05 + (the volume of blood sucked in suction bottle). The quantity of post-operative blood loss (mL) = weight of used pads—weight of pads prior to used

S.J. Dhivya Lakshmi [30]

Blood loss was collected through a suction container, operation table perineal sheet and mops

The quantity of blood loss (mL) = (weight of used materials—weight of materials prior to surgery) + (the volume of blood in suction container after delivery of placental)

Khing Rushulo [31]

Blood loss was collected through a suction container, pads

The quantity of intra-operative blood loss (mL) = (weight of used materials—weight of materials prior to surgery) + (the volume of blood sucked in suction bottle). The quantity of post-operative blood loss (mL) = weight of used pads—weight of pads prior to used

P. Malathi [32]

Blood loss was collected through a suction container, mops, surgical swabs, and linen

The quantity of intra-operative blood loss (mL) = (weight of used materials—weight of materials prior to used) + (the volume of blood sucked in suction bottle)

Samir Abd Allah Ali [33]

Blood loss was collected through a suction container, towels, and pads

The quantity of intra-operative blood loss (mL) = (weight of used towels—weight of towels prior to surgery) × 0.962 + (the volume of blood sucked in suction bottle). The quantity of post-operative blood loss (mL) = (weight of used pads—weight of pads prior to used) × 0.962

Ayman A. Soliman [34]

Blood loss was collected through sheets, pads, and gauzes

The quantity of blood loss (mL) = (weight of used materials—weight of materials prior to used)/1.06

Noshina Shabir [35]

Blood loss was collected through a suction container, operation sheets and mops

The quantity of intra-operative blood loss (mL) = (weight of used materials—weight of materials prior to used)/1.05 + (the volume of blood sucked in suction bottle). The quantity of post-operative blood loss (mL) = (weight of used materials—weight of materials prior to used)/1.05