Abstract Number: PB1294
Meeting: ISTH 2021 Congress
Background: Postpartum hemorrhage (PPH) is responsible for 30-50% of maternal deaths worldwide. Anemia appears to facilitate PPH. However, evidence is conflicting, derived mostly from a few studies applying strict World Health Organisation (WHO) definitions of PPH and/or anemia.
Aims: To study anemia and PPH risk by considering studies with conformant and non-conformant WHO definitions.
Methods: A MEDLINE database search was conducted applying the terms anemia OR hemoglobin AND postpartum hemorrhage. Study titles and abstracts were screened. Exclusion criteria were: not peer-reviewed, non-English, uterotonic studies, case reports, in-vitro/animal reviews.
Data extraction included: study type, sample size, PPH/anemia definition, anemia severity and information regarding associations of anemia and PPH. We used a random-effects meta-analysis model to estimate an overall odds ratio.
Results: Of 1060 articles, 1021 were excluded, leaving 39 studies originating from Africa (n=14), Asia (n=12), Europe (n=7), America/Oceania (n=2), South America (n=1) or multi-country (n=1). Only 46% and 15% of studies used the WHO definition for PPH and performed objective blood loss (OBL) measurements. The WHO definition of antepartum anemia (Hgb <11g/dL) was used in 76% of studies, with WHO sub-categorization by anemia severity in only 31%. The overall prevalence of anemia across studies ranged from 1-88%. Of 39 studies 32 reported positive associations between anemia and PPH (n=25) or adverse outcomes of anemia in PPH (n=7) (Figure 1).
A meta-analysis of studies providing crude ORs (n=12) showed a greater risk of PPH in patients with anemia (OR 1.47; 95% CI: 1.25, 2.33) (Figure 2).
Conclusions: Antepartum anemia appears to influence the risk of PPH and/or adverse maternal outcomes. However, this analysis revealed a lack of uniform definitions of PPH and anemia, OBL measurements and large geographic variations in anemia prevalence, altogether highlighting the need for harmonized prospective studies to inform future intervention strategies.
To cite this abstract in AMA style:Glonnegger H, Lancaster L, Barnes R, von Drygalski A. Antepartum Anemia and Risk of Postpartum Hemorrhage: A Comprehensive Review of the Literature [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 1). https://abstracts.isth.org/abstract/antepartum-anemia-and-risk-of-postpartum-hemorrhage-a-comprehensive-review-of-the-literature/. Accessed September 24, 2021.
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