“…The Hourly Fetal Urine Production Rate (HFUPR) can be estimated by regression analysis of calculated bladder volumes documented at different time points within one filling phase (Campbell et al, 1973;Fagerquist et al, 2001;Groome et al, 1991;Nicolaides et al, 1990;Rabinowitz et al, 1989;van Otterlo et al, 1977;Wladimiroff and Campbell, 1974), or by the difference between the maximum and minimum volumes divided by the time interval (Deutinger et al, 1987;Shin et al, 1987;Takeuchi et al, 1994). The filling and emptying dynamics of the fetal urinary bladder have been investigated in detail.…”