What is the normal range of obstetric shock index in the immediate postpartum period in a low‐resource setting?

Objective To determine the normal range of shock index (SI), blood pressure (BP), mean arterial pressure (MAP) and heart rate (HR) among postpartum women in a low‐resource setting. Methods In a prospective cohort study, vital signs were recorded 1 hour after delivery among postpartum women with normal blood loss who delivered in Abakaliki, Nigeria, from April to July 2019. Results Among 225 women, the median (95% reference range) was 120 (100–155.8), 70 (60–94), and 90 (66.5–116.6) mm Hg for systolic BP, diastolic BP, and MAP, respectively; 82 (65–102) bpm for HR; and 0.69 (0.48–0.89) for SI. The upper SI limit of 0.89 supported the current value of 0.9 as the upper limit; however, the lower SI limit of 0.48 corresponded to the current lower limit for a non‐obstetric population (0.5). The SI of more than half of the study women (n=126; 56.0%) was within the normal range for non‐obstetric women (0.5–0.7). Conclusion Although hemodynamic changes in pregnancy widen the SI range, 56.0% of women maintained SI within the non‐obstetric reference range. In low‐resource settings, the current normal obstetric SI range of 0.7–0.9 should be revised to 0.5–0.9 to accommodate this lower threshold. The normal range of obstetric shock index should be revised to 0.5–0.9 to accommodate the lower threshold observed in a low‐resource setting.