The Beneficial Effect of Progesterone on Pregnancy in the Vitamin A-Deficient Rabbit

Abstract

Fifty-eight adult female rabbits were placed on a carotenedeficient diet for varying lengths of time and were then mated to fertile males. The average litter size of the 22 females on the diet for 4 or 8 weeks was well below the normal of 8.3 and injections of 8 mg of progesterone in half of them had no apparent effect on litter size. The 14 females on the diet for 12 or 13 weeks before mating averaged 0.9 living and 0.6 dead young at autopsy on the 28th day of pregnancy, while 7 comparable females injected with 8 mg of progesterone daily had 4.3 living and 2.2 dead young and the 7 females receiving 12.5 mg of progesterone had 5.1 living and 3.4 dead young.