Subgroup analysis
The following pooled estimate rates were found in the subgroup analysis: 25.8% (95% CI 19.3 – 32.3) in extremely preterm; 23% (95% CI 17.7 – 28.2) in very preterm, and 11.6% (95% CI 5.5 – 17.7) in moderate/late preterm. All these analyses presented high heterogeneity (I2 = 87.7% to 98.8%) and are shown in Figure 3.