Amniotic fluid volume and fetal swallowing rate in sheep
To investigate amniotic fluid (AF) dynamics and volume regulatory mechanisms, the authors measured the concentration of radioiodinated (/sup 125/I) serum albumin (RISA), /sup 51/Cr-labeled red blood cells (Cr-RBC), and /sup 103/Ru-labeled microspheres after injection into the amniotic cavity and determined AF volume and fetal swallowing rate in 22 singleton pregnant sheep. Under normal conditions 2-3 h were required for complete mixing of RISA and Cr-RBC within AF; however, when the fetus was dead only 3-5 h were required. AF volume of 17 sheep on the 5th postoperative day averaged 975 +/- 128 ml by RISA and 986 +/- 130 ml by Cr-RBC. AF volume determined with RISA and Cr-RBC correlated well. In contrast, AF volume measurement with microspheres produced erratic results. The disappearance rate of the labels in 17 ewes on the 5th postoperative day averaged 4.9 +/- 0.7%/h for RISA and 5.5 +/- 0.7 for Cr-RBC, and the calculated rates of fetal swallowing were 935 +/- 78 ml/day by RISA and 1,085 +/- 102 by Cr-RBC. In dead fetuses the disappearance rates were almost zero, suggesting that the labels disappear mainly by swallowing. Absolute volume swallowed and swallowed volume per fetal weight correlated with gestational age. AF volume correlated with fetal weight. Radiolabeled albumin or red blood cells may be used to simultaneously measure amniotic fluid volume and the rate of fetal swallowing. Furthermore it appears that fetal swallowing increases with gestational age.
- Research Organization:
- Loma Linda Univ., CA
- OSTI ID:
- 5218187
- Journal Information:
- Am. J. Physiol.; (United States), Journal Name: Am. J. Physiol.; (United States)
- Country of Publication:
- United States
- Language:
- English
Similar Records
Fetal rat utilization of $sup 55$Fe absorbed by fetal intestine from swallowed amniotic fluid
Cardiac output distribution and uteroplacental blood flow in the pregnant rabbit: a comparative study
Related Subjects
AMNIOTIC FLUID
DYNAMIC FUNCTION STUDIES
INTAKE
AGE DEPENDENCE
ALBUMINS
CHROMIUM 51
ERYTHROCYTES
FETUSES
INGESTION
IODINE 125
LABELLED COMPOUNDS
MICROSPHERES
MIXING
PREGNANCY
RUTHENIUM 103
SHEEP
TRACER TECHNIQUES
VOLUME
WEIGHT
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
CHROMIUM ISOTOPES
DAYS LIVING RADIOISOTOPES
DOMESTIC ANIMALS
ELECTRON CAPTURE RADIOISOTOPES
EVEN-ODD NUCLEI
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
MAMMALS
MATERIALS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PROTEINS
RADIOISOTOPES
RUMINANTS
RUTHENIUM ISOTOPES
VERTEBRATES
551001* - Physiological Systems- Tracer Techniques