Maternal obesity, obstetric interventions and post-partum anaemia increase the risk of post-partum sepsis: a population-based cohort study based on Swedish medical health registers

Abstract

Background: The objective was to estimate whether maternal obesity and/or obstetric interventions are associated with diagnosed maternal post-partum sepsis.

Methods: A retrospective observational cohort study including all deliveries in Sweden between 1997 and 2012 (N = 1,558,752). Cases of sepsis (n = 376) were identified by International Classification of Diseases, (ICD-10) codes A40, A41 and O 85 in the Medical Birth Register and the National Patient Register. The reference population was non-infected, and therefore, women with any other infection diagnosis and/or with dispensed antibiotics within eight weeks post-partum were excluded. Information on dispensed drugs was available in the prescribed drug Register. Women with sepsis were compared with non-infected women concerning maternal characteristics and obstetric interventions. Adjusted odds ratios (aOR) were determined using the Mantel-Haenszel technique. Adjustments were made for maternal age, parity and smoking.

Results: Obese women (body mass index ≥30) had a doubled risk of sepsis (3.6/10,000) compared with normal weight women (2.0/10,000) (aOR 1.85 (95%CI: 1.37-2.48)). Induction of labour (aOR 1.44 (95%CI: 1.09-1.91)), caesarean section overall (aOR 3.06 (95%CI: 2.49-3.77)) and elective caesarean section (aOR 2.41 (95%CI: 1.68-3.45)) increased the risk of sepsis compared with normal vaginal delivery. Post-partum anaemia due to acute blood loss was associated with maternal sepsis (aOR 3.40 (95%CI: 2.59-4.47)).

Conclusions: Maternal obesity, obstetric interventions and post-partum anaemia due to acute blood loss increased the risk of diagnosed post-partum sepsis indicating that interventions in obstetric care should be considered carefully and anaemia should be treated if resources are available.

Keywords: Post-partum; anaemia; caesarean section; obesity; sepsis.