ABSTRACT [Word Count: 226]
OBJECTIVE: Our goal is to describe the association between
total quantitative blood loss (QBL) and risk of obstetric
hemorrhage-related morbidity (OBH-M) in order to assess utility of the
current definition of obstetric hemorrhage (OBH).
DESIGN: Retrospective cohort study.
SETTING: Urban safety-net hospital in Boston, Massachusetts.
POPULATION or SAMPLE: Deliveries at our institution over a
two-year period.
METHODS: We categorized deliveries into ten equally sized
deciles based on QBL and compared the proportion with OBH-M in each.
Among the two deciles with the highest proportions of OBH-M, we
stratified deliveries into seven groups of ascending intervals of 250cc
QBL. Finally, we compared the positive predictive value (PPV) of the
standard definition of OBH (QBL ≥ 1000cc) to a definition
extrapolated from our stratified analysis.
MAIN OUTCOME MEASURES: The primary outcome was proportion of
deliveries within each QBL decile affected by OBH-M. The secondary
outcome was PPV.
RESULTS: We found a significant increase in OBH-M from decile 9
(895-1201cc QBL) to decile 10 (1205-8325cc QBL) (p<0.001). In
our stratified analysis, we found QBL of 1500cc to be an inflection
point for an increased proportion of OBH-M. Our secondary analysis
showed an increased PPV for OBH-M using QBL of 1500cc (20.5%) compared
to that of QBL 1000cc (9.8%).
CONCLUSIONS: Our findings suggest that a higher QBL threshold
than the currently accepted definition of OBH is more predictive of
OBH-M.
FUNDING: This work was supported in part by the Boston
University Clinical and Translation Science Institute (NIH grant:
1UL1-TR001430).
KEYWORDS: obstetric hemorrhage, maternal morbidity,
quantitative blood loss