Table of Contents
ISRN Obstetrics and Gynecology
Volume 2011, Article ID 345431, 6 pages
Research Article

Fetal Urine Production in Late Pregnancy

Department of Perinatology & Gynecology, Wilhelmina Children's Hospital, University Medical Centre Utrecht, Lundlaan 6, 3584 EA Utrecht, The Netherlands

Received 8 April 2011; Accepted 10 May 2011

Academic Editors: D. Chen, J. G. Schenker, and K. Yang

Copyright © 2011 Robert H. Stigter et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Objective. Hourly fetal urine production rate (HFUPR) was studied in relation to both gestational age and the onset of spontaneous labor in normal term human pregnancies. Methods. Serial volume measurements were obtained from longitudinal ultrasound images of the fetal bladder at 1–5-minute intervals, and HFUPR was subsequently calculated. A total of 178 adequate bladder-filling cycles were recorded in 112 women, and the amniotic fluid index (AFI) was assessed. Results. HFUPR did not change significantly between 37 and 42 weeks' gestation. However, HFUPR decreased during the last 14 days prior to the onset of spontaneous labor ( ๐‘ƒ < 0 . 0 0 5 ). No significant correlation was found between HFUPR and AFI, neither when measured at the same time nor when HFUPR and AFI were measured at various intervals in time. Conclusion. HFUPR falls before and in relation to the time of onset of labor rather than in relation to gestational age.