Table 2 

Parity/age categories and their median and range of prevalence across included cohort studies 

Nulliparous 
Parity 12 (reference) 
Parity ≥3 



Age <18 
Median: 7.37% Range: 0.1312.74% N*=9 
Median: 0.76% Range: 0.012.65% N=0 
Median: 0.00 Range: 0.000.22% N=0 


Age 18<35 (reference) 
Median: 28.27% Range: 1.2043.72% N=14 
Median: 39.93% Range: 33.2851.50% N=14 
Median: 13.42% Range: 7.1735.64% N=14 


Age ≥35 
Median: 0.08% Range: 0.001.54% N=0 
Median: 0.71% Range: 0.006.30% N=2 
Median: 5.52% Range: 0.179.19% N=7 


Median and Range are described across all 14 cohort studies. *The Ns indicated reflects how many studies out of the 14 included studies have ≥5% prevalence in that category. 

Kozuki et al. BMC Public Health 2013 13(Suppl 3):S2 doi:10.1186/1471245813S3S2 