Fig. 9

Box plot showing relation between fetal head station by VE and fetal HPD by US. Box plot showing the relation between the fetal head station by VE and fetal head-perineum distance by US. The box represents the range from the first quartile to the third quartile (interquartile range). The line inside the box represents the median (second quartile). Error bars represent the minimum and maximum values. Kendall’s tau-b (τ) = − 0.299, 95% CI = − 0.479 to − 0.0863, p value = .0063