Amniotic fluid volume and composition in mouse pregnancy.
OBJECTIVE
The current study was undertaken to determine simultaneous changes in amniotic fluid (AF) volume and composition across gestation in the pregnant mouse.


METHODS
Young adult mice (6 to 7 weeks old) of the CB6F1 strain were mated overnight. AF was collected on consecutive days from embryonic days 9.5 through 18.5 for measurements of volume and composition. Statistical analysis included one-factor analysis of variance (ANOVA).


RESULTS
AF volume increased from 18 +/- 4 (SE) microL on day 9.5 to a maximum of 147 +/- 4 microL on days 15.5 to 16.5 and decreased sharply to 17 +/- 3 microL on day 18.5. AF osmolality was unchanged except for a rise prior to delivery on day 19.5 to 20.5. AF sodium, calcium, and glucose concentrations increased and subsequently decreased as gestation progressed. AF potassium, chloride, and lactate concentrations initially decreased and then increased across gestation. Prior to day 9.5 and after day 18.5, AF volume was too small for volume or compositional determinations.


CONCLUSIONS
In the mouse, the rise in AF volume from mid gestation to a maximum late in gestation is similar to that in humans while the sharp fall prior to delivery is not. As observed in the fetal sheep, the changes in fluid volume are associated with AF osmolality and solute concentration changes that are correlated with advancing gestational age. These observations together with the feasibility of quantifying AF volume and composition in the mouse fetus demonstrate the possibility of using genetically altered mice as a model for future studies on the molecular mechanisms underlying the regulation of AF volume and composition.
Cheung
Cecilia Y
CY
Division of Perinatal Medicine, Department of Reproductive Medicine, University of California San Diego, La Jolla, California 92093-0802, USA. cycheung@ucsd.edu
Brace
Robert A
RA
D000653:Amniotic Fluid / Q000737:chemistry / Q000502:physiology; D000818:Animals; D002118:Calcium / Q000032:analysis; D002712:Chlorides / Q000032:analysis; D005260:Female; D005333:Fetus; D005865:Gestational Age; D005947:Glucose / Q000032:analysis; D019344:Lactic Acid / Q000032:analysis; D051379:Mice; D008815:Mice, Inbred Strains; D023421:Models, Animal; D009994:Osmolar Concentration; D011188:Potassium / Q000032:analysis; D011247:Pregnancy; D012964:Sodium / Q000032:analysis
D002712:Chlorides; D019344:Lactic Acid; D012964:Sodium; D005947:Glucose; D011188:Potassium; D002118:Calcium