Retinol is specifically required during midgestation for neonatal survival.

Previous work has demonstrated that vitamin A-deficient, retinoic acid-supplemented pregnant rats cannot complete gestation without the administration of retinol. As little as 2 micrograms administered on day 10 of gestation is sufficient to prevent the characteristic fetal resorption that begins at day 15 of gestation. This single dose of retinol supports continued development through day 20 of gestation. However, if gestation is allowed to proceed to parturition, the newborn pups die within a few minutes of being severed from the umbilical cord. The pups are born with a pink and healthy skin tone, but within seconds of umbilical separation, they begin to gasp for air, become cyanotic in appearance, and die within several minutes from an apparent inability to obtain oxygen. Histological examination of these neonates demonstrates delayed pulmonary development. Branching and scalloping of ducts and saccule and subsaccule formation are decreased. This phenotype is consistent with that observed in respiratory distress syndrome seen in some premature human infants.