Changes in amniotic fluid volume and total solute concentration in the rhesus monkey following replacement with distilled water

Changes in amniotic fluid total solute composition and volume in the rhesus monkey following replacement of this fluid with equal volumes of distilled water are described. Initial reduction of total solute concentration of this fluid was rapidly corrected over the next 18 to 20 hours. This correction was achieved by a combination of net transfer of water out of the amniotic fluid compartment and of net transfer of solute, principally sodium and corresponding anions, back into the sac. 131I-albumin dilution is shown to be a reliable method for measuring amniotic fluid volume in the rhesus monkey. The range of measured volumes increases with gestational age; no other meaningful correlation is seen in the data obtained.