Maternal and embryonic response to a "carbohydrate-free" diet fed to rats

The effects of a carbohydrate-free, fatty acid (CF) diet on pregnant rats and their progeny were examined. A pregnant pair-fed group was included to compensate for the 40% reduction in food intake of the CF dams. Control and CF dams were killed on days 6, 8, 10, 12, or 14 of gestation. Pair-fed dams were killed on day 14. Maternal CF rats were hypoglycemic and hyperketonemic as compared to pair-fed or control dams. Both CF and pair-fed dams had significantly reduced liver glycogen. Diet had no effect on the number of implantation sites. Conceptuses were classified histologically as normal, retarded, malformed, degenerating or resorbed. Numbers of normal CF embryos were significantly reduced from day 6 and, by day 12, all CF embryos had been resorbed. Control and pair-fed dams showed 5.2% and 43.8% resorptions, respectively, on day 14. These data suggest that approximately half of the embryonic loss can be attributed to the reduction in food intake whereas the remaining embryos succumbed to embryolethal conditions more directly related to the metabolic consequences of carbohydrate deprivation.