ObjectiveTo evaluate the effect of different rehydration strategies on the incidence of spinal anesthesia-induced hypotension and neonatal outcomes during elective cesarean section.MethodsWe searched PubMed, Embase, the Cochran Library, China National Knowledge Internet, VIP database, Wanfang database, and China Biology Medicine database from inception to January 2018, to collect randomized controlled trials (RCTs) about the incidence of spinal anesthesia-induced hypotension during elective cesarean section and neonatal outcomes of preloading or coloading. Two researchers independently screened the literature, extracted data, and evaluated the risk of bias in the study. Meta-analysis was conducted using RevMan 5.3 software.ResultsA total of 11 RCTs were included, including 894 parturients, of whom 448 cases in the preload group and 446 cases in the coload group. Comparing with the preload group, the incidence of spinal anesthesia-induced hypotension during cesarean section in the coload group significantly decreased [risk ratio (RR)=1.27, 95% confidence interval (CI) (1.13, 1.43), P<0.000 1]. Subgroup analysis showed that in the crystalloid fluid group, the difference in the incidence of hypotension between the preload group and the coload group was statistically significant [RR=1.48, 95%CI (1.26, 1.73), P<0.000 01]; while in the colloidal fluid group, the difference in the the incidence of hypotension between the preload group and the coload group was not significant [RR=1.00, 95%CI (0.85, 1.17), P=0.96]. The lowest systolic blood pressure, the incidence of nausea and vomiting, and neonatal outcomes had no significant difference between the two groups.ConclusionsComparing with preloading crystalloid fluid, rapid infusion of crystalloid fluid at the same time implementation of spinal anesthesia could significantly reduce the incidence of hypotension during cesarean section while there was no superiority in infusion of colloid fluid. There was no significant effect on the severity of hypotension, nausea and vomiting, and neonatal outcomes. Due to the limitation of the quantity and quality of the included studies, the above conclusions need to be verified by more high-quality studies.