Statistical analysis
Means and standard deviations were used to summarise normally distributed variables and compared using a t-test, while medians and interquartile ranges were used and compared using a Mann-Whitney U test for non-normally distributed variables. Categorical variables were summarised as counts and percentages, and compared using a Chi-squared test. To explore the association between APH and the various obstetrics outcomes, we used logistic, negative binomial and Poisson regression as appropriate. All analyses were conducted using STATA version 15.1 (Stata Corporation, College Station, Texas, USA).