Factors associated with severe postpartum haemorrhage: systematic review using Bradford Hill’s causality framework

Abstract

Back Background ground Severe postpartum haemorrhage (S-PPH) is the leading cause of maternal death worldwide. We aimed to provide an up-to-date summary about S-PPH determinants. Methods Methods We performed a systematic review following the Preferred Reporting Items for Systematic reviews and Meta-analysis (PRISMA) guidelines. We searched the terms "risk factor", "determinant", "post-partum haemorrhage" and "severe", within Web of Science, Scopus, Science Direct, Medline, Cochrane, and Clinical Trials.gov databases. The primary endpoint was S-PPH, defined as a blood loss ≥1,000 mL a second-line treatment, a PPH-related blood transfusion, a peripartum decrease in haemoglobin level or a PPH-related maternal death. All interventional and observational studies about risks factors for S-PPH published in English or French between January 1, 2004 and August 31, 2018 were eligible. Because studies used very different definitions of S-PPH, meta-analysis was ruled out and we gauged the risk factors using the Bradford Hill's criteria causality framework. R Results esults Amongst 1,193 identified abstracts, we selected fourteen studies that collected information on 9,271,519 parturient women (35,825 with S-PPH). Key established determinants of S-PPH were previous PPH, previous caesarean, multiple pregnancy, abnormal placentation, preeclampsia, labour induction, prolonged labour, placental retention, uterine rupture, uterine atony, uterine fibroids, macrosomia, birth canal injuries, instrumental vaginal and caesarean deliveries. Most of associated factors of uncertain significance belonged to socio-environmental characteristics. Biological parameters were all classified as indicators of risk. C Conclusions onclusions The key established determinants of S-PPH are of primarily obstetrical nature. New avenues of research, including contextual studies, are needed to improve the management of severe obstetrical morbidity.

Assessment of Postpartum Hemorrhage in a University Hospital in Eastern Ethiopia: A Cross-Sectional Study

“…We found that women with history of PPH were more likely to experience PPH than their counterparts 16 indicating the importance of counseling women about recurrence of PPH in subsequent pregnancies. Congruent with previous findings, PPH was more likely among women with no ANC follow up.…”

“…Moreover, magnitude of PPH may vary between and within geographical regions as a result of variation in diagnosis, quality of documentation or due to subjective estimation of blood loss). 17,[23][24][25][26] We found that women with history of PPH were more likely to experience PPH than their counterparts 16 indicating the importance of counseling women about recurrence of PPH in subsequent pregnancies. Congruent with previous findings, PPH was more likely among women with no ANC follow up.…”

“…28 Similarly, grand multigravida (≥5) women were more likely to develop PPH in line with the finding from Cameroon. 16,25 Repeated stretching of 666 muscle fibers may lead to loss of muscle tone that results in uterine atony which is the leading cause of PPH. 29 The high burden of PPH in our study indicates the importance of auditing the appropriateness of obstetric management in HFSUH.…”

“… 28 Similarly, grand multigravida (≥5) women were more likely to develop PPH in line with the finding from Cameroon. 16 , 25 Repeated stretching of muscle fibers may lead to loss of muscle tone that results in uterine atony which is the leading cause of PPH. 29 …”

“…14 PPH is more likely among women with macrosomia, those who had histroy of PPH, previous cesarean, abnormal placentation, prolonged third stage of labor, hypertensive disorders of pregnancy, soft tissue lacerations or induction of labor. [15][16][17] Active management of the third stage of labor is the most effective strategy for prevention of PPH. 18 Given the risk of under reporting among studies because of the focus on deaths or severe forms of morbidity from PPH, 19,20 studies focusing on the overall morbidity from PPH are essential to reveal the burden of the problem for designing appropriate preventive services and planning for resource allocation.…”