Vitamin A requirements assessed by plasma response to supplementation during pregnancy.

Plasma vitamin A responses were examined in 30 low income pregnant women before and after supplementation with vitamin A. In the groups of women who had an initial (at < 20 weeks) plasma vitamin A of less than 30 micrograms/dl retinol, typical changes representing a peak at mid gestation and a significant decline at term were observed. Supplementation with vitamin A tablets equivalent to 1800 micrograms of retinol daily for 12 weeks was able to raise the plasma vitamin A content at term. On the other hand, those women who had an initial plasma vitamin A concentration of more than 30 micrograms/dl did not show any appreciable changes even with vitamin A supplementation. Consistent beneficial effects of supplementation on maternal and cord vitamin A and maternal hemoglobin and progesterone were noted in our previous studies only when the supplementation lasted for 12 weeks and not after 10 weeks. Using these data with dietary intake obtained from other studies, an attempt was made to estimate the requirements of vitamin A during pregnancy. The approximate requirement of 780 retinol equivalents (RE) obtained, is in agreement with earlier recommendations of FAO and Indian Council of Medical Research (ICMR) Expert Committees, but is higher than the recent ICMR recommendations.