Open Access Research article

Calibrated delivery drape versus indirect gravimetric technique for the measurement of blood loss after delivery: a randomized trial

Shubha Ambardekar1, Tara Shochet2*, Hillary Bracken2, Kurus Coyaji1 and Beverly Winikoff2

Author Affiliations

1 Department of Obstetrics & Gynecology, K.E.M. Hospital, Pune, India

2 Gynuity Health Projects, New York, NY, USA

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BMC Pregnancy and Childbirth 2014, 14:276  doi:10.1186/1471-2393-14-276

Published: 15 August 2014



Trials of interventions for PPH prevention and treatment rely on different measurement methods for the quantification of blood loss and identification of PPH. This study’s objective was to compare measures of blood loss obtained from two different measurement protocols frequently used in studies.


Nine hundred women presenting for vaginal delivery were randomized to a direct method (a calibrated delivery drape) or an indirect method (a shallow bedpan placed below the buttocks and weighing the collected blood and blood-soaked gauze/pads). Blood loss was measured from immediately after delivery for at least one hour or until active bleeding stopped.


Significantly greater mean blood loss was recorded by the direct than by the indirect measurement technique (253.9 mL and 195.3 mL, respectively; difference = 58.6 mL (95% CI: 31–86); p < 0.001). Almost twice as many women in the direct than in the indirect group measured blood loss > 500 mL (8.7% vs. 4.7%, p = 0.02).


The study suggests a real and significant difference in blood loss measurement between these methods. Research using blood loss measurement as an endpoint needs to be interpreted taking measurement technique into consideration.

Trial registration

This study has been registered at as NCT01885845.

Postpartum blood loss; Postpartum blood measurement