The retained placenta: historical and geographical rate variations.

In this study, we sought to explore the variation in reported rates of retained placenta around the world and over time in the UK. A systematic review of observational studies was performed to obtain retained placenta rates from around the world and annual hospital reports from the Royal College of Obstetricians and Gynaecologists archives were examined to obtain historical retained placenta rates. The data show that the median rate of retained placenta at 30 minutes was higher in developed countries (2.67% vs 1.46%, p < 0.02), as was the median manual removal rate (2.24% vs 0.45%, p < 0.001). In addition to this, there appears to have been a rise in rate of manual removal in the UK from a mean of 0.66% in the 1920s to 2.34% in the 1980s (p < 0.0001).