Serum and liver concentrations of vitamin A in Thai fetuses as a function of gestational age.

Serum and liver vitamin A values were determined in 26 male and 20 female Thai fetuses varying in gestational age from 13 weeks to term. In general pregnancies were of healthy young women from the Bangkok area. The median, mean and range of fetal serum retinol values (+/- SE) were 25.8, 30.7 +/- 3.0, and 1.9 to 109.6 microgram/100 ml, and of liver values were 16.4, 19.4 +/- 2.2, and 1.1 to 51.6 microgram retinol per gram of liver. Median and mean serum and liver values were about 10% higher in males than in females, but not significantly so. Serum retinol concentrations neither correlated with liver concentrations, except below 5 microgram/g, nor served as a valid indicator of total liver stores of vitamin A. Serum retinol values declined slowly with gestational age to term, whereas liver vitamin A concentrations tended to increase until the 28th week and then to fall until term. Whereas the liver to body weight ratio remained essentially constant (0.0425 +/- 0.003, P less than 0.0001) during the gestational period, vitamin A concentrations in both serum and liver showed marked variability.