The Edmonton Obesity Staging System and pregnancy outcomes in women with overweight or obesity: A secondary analysis of a randomized controlled trial

The Edmonton Obesity Staging System (EOSS) is a proposed clinical practice tool to determine obesity severity. In a secondary analysis of the Pregnancy Exercise and Research Study (PEARS) (a mobile‐health‐supported lifestyle intervention among pregnant women with body mass index [BMI] ≥25 kg/m(2)), we apply the EOSS and explore relationships with pregnancy outcomes. In early (14–16 weeks) and late (28 weeks) pregnancy, fasting lipids and glucose were measured, blood pressure was extracted from medical records and maternal well‐being was assessed using the WHO‐5 Well‐being Index. Pearson's correlations, chi‐square statistics and multiple logistic regression were used to identify relationships. One‐way analysis of variance was used to compare groups. Pregnant women (n = 348) were mean (SD) age 32.44 (4.39) years and median (interquartile range) BMI 28.0 (26.57, 29.88) kg/m(2). Using metabolic criteria only, 81.9% and 98.9% had raised EOSS scores in early and late pregnancy. From early to late pregnancy, EOSS scores increased by 60.1%. Of these, 10.5% experienced a 2‐point increase, moving from stage 0 to stage 2. There was a potential relationship between early EOSS and large for gestational age (χ (2) = 6.42, df (2), p = .04), although significance was lost when controlled for confounders (p = .223) and multiple testing. Most women with BMI ≥25 kg/m(2) had raised EOSS scores, limiting the clinical utility of the tool.