Daily injections of estrone and progesterone, given separately or combined, failed to prevent fetal death and resorption in rats deficient in pantothenic acid or in pteroylglutamic acid (PGA). The dosage levels of the hormones were the same as those used successfully to maintain pregnancy in rats hypophysectomized and oophorectomized after breeding as well as in rats deficient in thiamine, pyridoxine, protein or K. Under the experimental conditions, reproductive failure in rats subjected to pantothenic acid or PGA-deficiency did not appear to be due to lack of the maternal sex hormones.[long dash].