Glycosylated hemoglobins in normal pregnancy: sequential changes and relation to birth weight.

In order to evaluate changes in hemoglobin A1 levels during nondiabetic pregnancy, 19 pregnant women were followed by determination of hemoglobin A1 with a two to four week interval. There was an early decrease in the hemoglobin A1 level already between the 12th and 16th weeks of pregnancy, with a further decrease in the course of the pregnancy. This physiologic fall in hemoglobin A1 during nondiabetic pregnancy could be important in evaluation of hemoglobin A1 changes in diabetic pregnancies. Correlations between different levels and changes in hemoglobin A1 and relative birth weight were also calculated. Relative birth weight was best correlated to the changes in hemoglobin A1 during the third trimester (r = 0.56, P less than .01), which suggests that availability of glucose is one factor determining fetal growth during the last trimester.