Effect of Electrolyte Disturbances in the Pregnant Rabbit on the Fetus

¹ From the Departments of Pediatrics and Obstetrics and Gynecology, New York University-Bellevue Medical Center, New York City

The possibility that the placenta may protect the fetus against electrolyte disturbances in the mother was investigated in rabbits. Hyperosmolarity of the blood of the doe was induced with intravenous infusions of hypertonic sucrose. The osmotic pressure of the fetal blood approximated that of the mother within an hour and possibly considerably sooner. Acidosis was induced with ammonium chloride. The maternal plasma chlorides were in creased for roughly 3 hours before the fetal chlorides showed similar increases. However, after prolonged acidosis the fetal electrolyte changes paralleled the maternal with a lowered ph and CO₂ content and elevated plasma chlorides.