The Continuum of Maternal Sepsis Severity: Incidence and Risk Factors in a Population-Based Cohort Study

Abstract

ObjectiveTo investigate the incidence and risk factors associated with uncomplicated maternal sepsis and progression to severe sepsis in a large population-based birth cohort.MethodsThis retrospective cohort study used linked hospital discharge and vital statistics records data for 1,622,474 live births in California during 2005–2007. Demographic and clinical factors were adjusted using multivariable logistic regression with robust standard errors.Results1598 mothers developed sepsis; incidence of all sepsis was 10 per 10,000 live births (95% CI = 9.4–10.3). Women had significantly increased adjusted odds (aOR) of developing sepsis if they were older (25–34 years: aOR = 1.29; ≥35 years: aOR = 1.41), had ≤high-school education (aOR = 1.63), public/no-insurance (aOR = 1.22) or a cesarean section (primary: aOR = 1.99; repeat: aOR = 1.25). 791 women progressed to severe sepsis; incidence of severe sepsis was 4.9 per 10,000 live births (95% CI = 4.5–5.2). Women had significantly increased adjusted odds of progressing to severe sepsis if they were Black (aOR = 2.09), Asian (aOR = 1.59), Hispanic (aOR = 1.42), had public/no-insurance (aOR = 1.52), delivered in hospitals with <1,000 births/year (aOR = 1.93), were primiparous (aOR = 2.03), had a multiple birth (aOR = 3.5), diabetes (aOR = 1.47), or chronic hypertension (aOR = 8.51). Preeclampsia and postpartum hemorrhage were also significantly associated with progression to severe sepsis (aOR = 3.72; aOR = 4.18). For every cumulative factor, risk of uncomplicated sepsis increased by 25% (95% CI = 17.4–32.3) and risk of progression to severe sepsis/septic shock increased by 57% (95% CI = 40.8–74.4).ConclusionsThe rate of severe sepsis was approximately twice the 1991–2003 national estimate. Risk factors identified are relevant to obstetric practice given their cumulative risk effect and the apparent increase in severe sepsis incidence.

Progression from severe sepsis in pregnancy to death: a UK population‐based case‐control analysis

“…The association between sepsis and parity, which was not explained by age, ethnicity, employment status, smoking or BMI in our study, appears to be inconsistent in the literature, with studies finding increased risk for multiparous9 or nulliparous women 6, 10. This may be due to differences in the study populations, methods or adjustment for confounding.…”

“…These include studies of sepsis in obstetric populations,6, 9, 10, 11, 30 and other morbidities in obstetric populations 12, 13, 14, 27, 31, 32. Interestingly, all those studies found an effect of at least one socio‐demographic factor, most commonly age, body mass index (BMI) or ethnicity.…”

“…Several studies have compared women with severe sepsis to those with uncomplicated sepsis or normal pregnancies,6, 9, 10, 11 which will reflect factors that affect the incidence of sepsis, as well as progression of disease. However, no population‐based studies have compared sepsis‐related maternal deaths with morbidities, although this approach can highlight factors more pertinent to the most severe outcomes 12, 13, 14…”

Beyond maternal death: improving the quality of maternal care through national studies of ‘near-miss’ maternal morbidity

“…2,[99][100][101] Sepsis is estimated to cause 9.7% of maternal deaths in Africa, 11.6% in Asia and 7.7% in Latin America and the Caribbean combined. 102 In 2006-8, the UK maternal mortality rate from genital tract sepsis was 1.13/100,000 maternities, a rate not seen since the early 1970s, 100,103 and in 2009-12, one-quarter of all maternal deaths were due to infectious causes.…”

“…Recent work has suggested an approximate doubling of the incidence of maternal sepsis in the USA since 2003. 99 Key information gaps in the understanding of this pressing problem are the number of women affected, causative organisms, sources of infection and risk factors for severe sepsis and poor outcomes such as septic shock. Sepsis progresses along a spectrum of severity, so clarity about these factors has urgent implications for clinical management and infection control strategies to avoid preventable maternal deaths.…”