Hospital Data Reporting on Postpartum Hemorrhage: Under-Estimates Recurrence and Over-Estimates the Contribution of Uterine Atony

Abstract

(250 words)Objectives: This study aimed to explore whether recording of a prior adverse pregnancy outcome in a medical record increases the likelihood that recurrence of the same event is reported in population data. Methods:Using a random sample of 294 women who had first and second pregnancies in NSW, and a postpartum hemorrhage (PPH) reported for at least one pregnancy, we compared 'coded' recurrence rates in hospital data with those obtained from medical record audit. 'Coded' recurrence in a second pregnancy was also compared for women with or without a documented history of prior PPH. Results:We found a 'coded' recurrence rate of 18.5% and a 'true' rate (according to medical record audit) of 28.4%. The 'coded' rate of recurrence among women who had a documented history of PPH was 27.4% compared to 19.1% among those where the previous PPH was not noted in the second pregnancy medical record. 'True' reporting of a uterine atony cause for postpartum hemorrhages in first and second births was 37.9% and 34.0% while 'coded' hospital data reporting was 79.8% and 73.9% respectively. Conclusions:Our study results indicate that a history of postpartum hemorrhage may be an even stronger risk factor for subsequent PPH than previously demonstrated. A recorded history of PPH was associated with a higher likelihood of reporting a subsequent PPH, however in such cases recurrence rates approximate true recurrence. The contribution of uterine atony as a cause of postpartum hemorrhage is over-estimated using population health data.

Prevalence and Risk Factors of Severe Postpartum Hemorrhage: a Retrospective Cohort Study

“…Women with a history of PPH had 4.94-fold increased odds of SPPH. Likewise, a study from Australia reported a recurrence rate of 28% from medical audits [27]. A study from Sweden reported that the recurrence of PPH might be explained by environmental and genetic factors [28].…”

Risk factors for severe postpartum hemorrhage: a case-control study

“…Having a history of PPH may be less well-reported to the registries than in our data sources. Likewise, a validation study from Australia [28] reported a recurrence rate of 28% from medical record audits, while the reported recurrence rate in register based data was 18%. The causes of PPH recurrence were investigated in a population study from Sweden [27].…”

“…False reporting of cases caused by retained placental tissue as atonic bleeding in registries could explain this discrepancy. In a validation study examining the contribution of uterine atony to PPH [28], the incidence of uterine atony was overestimated by 10% when registry data were compared with clinical data. Access to detailed medical information enabled us to accurately estimate the proportion of cases with placental problems in our population.…”

Characteristics, causes and treatment of postpartum haemorrhage in first and second pregnancies

“…We utilised data collected in a review of PPH among 294 women with first and second pregnancies (representing 588 pregnancy records) and at least one PPH. The details of this study are reported elsewhere . Briefly, state birth data were used to select a random sample of 600 first and second birth records for 300 women giving birth in a selected Area Health Service in New South Wales (NSW) (2002–2006), and hospital separation data were used to identify where a PPH occurred after either or both pregnancies.…”

“…Canadian and USA studies suggest that such increases are driven by increases in uterine atony, which is purported to be the cause of three‐quarters of postpartum haemorrhages in high resource settings . However, the accuracy of reporting of the cause of PPH has been questioned …”