Abstract
The growth of 73 erythroblastotic infants (18 mild, 19 moderate, and 36 severe) was followed. In all three grups the average centiles for weight rose during the first half of the year. There was a fall in centiles during the second half of the year in 35 of 55 infants, 17 of them dropping below their birth centiles. Throughout the first year of life there was a strong correlation between serum folate of 8 mug/1 or more and rising weight centiles, and 5 mug/1 or less and falling centiles. None of the infants had macrocytic anaemia and their haemoglobin level rose even when their weight gain fell below the expected rate. It is suggested that in some erythroblastotic infants a shortage of folic acid may be a limiting factor for a normal growth rate.