Glycosylated haemoglobin (HbA1c) levels in normal pregnancy: sequential changes and relation to birth weight.

Twenty-five healthy pregnant females with the absence of family history of diabetes mellitus were investigated serially for glycosylated haemoglobin (HbA1c) as per cent haemoglobin A1 at the interval of 4 weeks. HbA1c values were also determined in 10 healthy non-pregnant females who were studied as control cases. As compared to non-pregnant females HbA1c values were found to be low at 14-16 weeks of pregnancy (4.9 +/- 0.25%). After 16 weeks the HbA1c levels showed an upward trend to reach maximum at 32-34 weeks (5.54 +/- 0.19%). After 34 weeks the levels fell again to reach the lowest by 40 weeks of gestation (4.8 +/- 0.203%). Statistically highly significant relationship (p less than 0.001) was found between the HbA1c values and birth weight, lower values were associated with low birth weight and with increasing HbA1c values birth weight was found to be correspondingly increased.