**1. Introduction**

132 From Preconception to Postpartum

World Health Organization. (1994). Mother-Baby-Package: implementing safe motherhood

Division of Family Health, WHO, Geneva. 1994.

in countries. Practical Guide. Maternal health and safe motherhood programmes,

Fetal urine production begins in the first trimester. Autopsy findings of filled urinary bladders in human fetuses have been reported from 11 gestational weeks (Abramovich, 1968). In 1970, the first report on ultrasound investigations of the fetal urinary bladder was published (Garrett et al., 1970). Three years later, a method for estimating fetal urine production was introduced (Campbell et al., 1973).

In this paper, a short summary of amniotic fluid turnover is presented. Moreover, fetal renal development, artery flow velocity and urine production in normal and compromised fetuses are dealt with. The gradual development of the 2D ultrasound technique for estimating of the fetal urine production rate (HFUPR) is described. In addition, some confounding factors are mentioned. Finally, two important clinical questions, which must be taken into consideration when utilising the HFUPR for fetal surveillance, are identified.
